diff --git a/ch_1_assign_kathy_li.py b/ch_1_assign_kathy_li.py
new file mode 100644
index 0000000..931fc94
--- /dev/null
+++ b/ch_1_assign_kathy_li.py
@@ -0,0 +1,110 @@
+#This is the dictionary that stores all the information about the teams.
+teams_info = {
+	1678: {
+		'location': 'Davis, California, USA', 
+		'rookie year': 2005,
+		'competed in 2019?': True,
+		'2019 competitions': [
+			'Central Valley Regional (Fresno, California, USA)',
+			'Sacramento Regional (Davis, California, USA)',
+			'Aerospace Valley (Lancaster, California, USA)',
+			'Carver Division - Houston Championship (Houston, Texas, USA)', 
+			'Einstein Field - Houston Championship (Houston, Texas, USA)', 
+			'RCC Qianjiang International Robotics Invitational (Hangzhou, Zhejiang, China)', 
+			'Chezy Champs (San Jose, California, USA)',
+		],
+		'2019 season awards': [
+			'Chairman\'s Award, Central Valley Regional',
+			'Winner, 2019 Central Valley Regional',
+			'FIRST Dean\'s List Finalist Award, Sacramento Regional (Katie Stachowicz)',
+			'Industrial Design Award (sponsored by General Motors), Sacramento Regional',
+			'Winner, 2019 Sacramento Regional',
+			'Excellence in Engineering Award (sponsored by Delphi), Aerospace Valley Regional',
+			'Winner, 2019 Aerospace Valley Regional',
+			'Entrepreneurship Award (sponsored by Kleiner Perkins Caufield and Byers)',
+			'Winner, 2019 Carver Division - Houston Championship',
+		]
+	},
+	1868: {
+		'location': 'Mountain View, California, USA',
+		'rookie year': 2006,
+		'competed in 2019?': True,
+		'2019 competitions': [
+			'Los Angeles North Regional (Valencia, California, USA)',
+			'Silicon Valley Regional (San Jose, California, USA)',
+			'Turing Division - Houston Championship (Houston, TX)',
+			'Chezy Champs (San Jose, California, USA)',
+		],
+		'2019 season awards': [
+			'Chairman\'s Award, Los Angeles North Regional',
+			'Winner, 2019 Los Angeles North Regional',
+			'Entrepreneurship Award (sponsored by Kleiner Perkins Caufield and Byers), Silicon Valley Regional',
+		]
+	},
+	1323: {
+		'location': 'Madera, California, USA',
+		'rookie year': 2004,
+		'competed in 2019?': True,
+		'2019 competitions': [
+			'Central Valley Regional (Fresno, California, USA)',
+			'Sacramento Regional (Davis, California, USA)',
+			'Newton Division - Houston Championship (Houston, Texas, USA)',
+			'Einstein Field (Houston, Texas, USA)',
+		],
+		'2019 season awards': [
+			'Autonomous Award (sponsored by Ford), Central Valley Regional',
+			'Winner, 2019 Central Valley Regional',
+			'Quality Award sponsored by Motorola Solutions Foundation',
+			'Winner, 2019 Sacramento Regional',
+			'Industrial Design Award (sponsored by General Motors), Houston Championship '
+			'Winner, 2019 Newton Division - Houston Championship',
+			'Winner, 2019 Houston Championship',
+		]
+	},
+	3132: {
+		'location': 'Sydney, Australia',
+		'rookie year': 2010,
+		'competed in 2019?': True,
+		'2019 competitions': [
+			'Southern Cross Regional (Sydney, Australia)',
+			'South Pacific Regional (Sydney, Australia)',
+			'Carver Division - Houston Championship (Houston, Texas, USA)',
+			'Einstein Field - Houston Championship (Houston, Texas, USA)',
+			'Duel Down Under (Sydney, Australia)',
+		],
+		'2019 season awards': [
+			'Woodie Flowers Finalist Award, Southern Cross Regional (Sarah Heimlich)',
+			'Gracious Professionalism Award (sponsored by Johnson & Johnson), Southern Cross Regional',
+			'Regional Engineering Inspiration Award, South Pacific Regional',
+			'FIRST Dean\'s List Finalist Award, South Pacific Regional (Jaye Heimlich)',
+			'Safety Award (sponsored by Underwriters Laboratories), South Pacific Regional',
+			'Winner, 2019 Carver Division - Houston Championship',
+		]
+	},
+	254: {
+		'location': 'San Jose, California, USA',
+		'rookie	year': 1999,
+		'competed in 2019?': True,
+		'2019 competitions': [ 
+			'San Francisco Regional (San Francisco, California, USA)',
+			'Silicon Valley Regional (San Jose, California, USA)',
+			'Turing Division - Houston Championship (Houston, Texas, USA)',
+			'Einstein Field - Houston Championship (Houston, Texas, USA)',
+			'Chezy Champs (San Jose, California, USA)'
+		],
+		'2019 season awards': [
+			'Innovation in Control Award (sponsored by Rockwell Automation), San Francisco Regional',
+			'Winner, 2019 San Francisco Regional',
+			'Excellence in Engineering Award (sponsored by Delphi), Silicon Valley Regional',
+			'Winner, 2019 Silicon Valley Regional',
+			'Industrial Design Award (sponsored by General Motors), Turing Divions'
+			'Winner, 2019 Turing Division - Houston Championship',
+			'Championship Finalist, Einstein Field - Houston Championship',
+
+		]
+	},
+}
+team_input = int(input('Choose an FRC team: 1678, 1868, 1323, 3132, or 254.\n'))
+team_attribute = input('Enter an attribute: "Location", "Rookie Year", "Competed in 2019?", "2019 Competitions", and "2019 Season Awards".\n').lower()
+#without .lower(), user input is case-sensitive.
+print(teams_info[team_input][team_attribute])
\ No newline at end of file
diff --git a/ch_1_lesson_{Kathy}_{Li}.py b/ch_1_lesson_{Kathy}_{Li}.py
new file mode 100644
index 0000000..8c854ae
--- /dev/null
+++ b/ch_1_lesson_{Kathy}_{Li}.py
@@ -0,0 +1 @@
+print('Hello, world!')
\ No newline at end of file
diff --git a/ch_2_assign_kathy_li.py b/ch_2_assign_kathy_li.py
new file mode 100644
index 0000000..06d63db
--- /dev/null
+++ b/ch_2_assign_kathy_li.py
@@ -0,0 +1,137 @@
+teams = {}
+while True: 
+	user_action = input("Welcome to the menu. Please select an action: add, remove, modify, view, search, or list. To quit, enter quit. \n")
+	
+	if user_action == "list":
+		print(teams)
+		continue
+
+	elif user_action == "remove": 
+		delete_team = int(input("Which team would you like to remove? Enter 0 to return to the menu. \n"))
+		if delete_team == 0:
+			continue
+		elif delete_team in teams.keys():
+			teams.pop(delete_team)
+			print("Team " + str(delete_team) + " has been removed.  ")
+			continue
+		else: 
+			print("Team " + str(delete_team) + " has not been found.  ")
+			continue
+	
+	elif user_action == "modify": 
+		update_team = input("Which team would you like to modify? To return the to the menu, enter 0. \n")
+		if update_team.isnumeric(): 
+			update_team = int(update_team)		
+			if update_team == 0:
+				continue
+			elif update_team in teams.keys():
+				update_variable = input("Which field would you like to modify: name, programming language, width, length, number of drivetrain motors, or camera vision? \n")
+				if update_variable not in teams[update_team].keys():
+					print("There is no such field. ")
+					continue
+				change = input("Enter the new value. \n")
+				if update_variable in ["width", "length", "number of drivetrain motors"]: 
+					if not change.isnumeric():
+						print("Input is invalid.  ")
+						continue
+					else:
+						teams[update_team][update_variable] = change
+						print("Successfully changed.   ")
+						continue
+				elif update_variable == "camera vision":
+					if change != "True" and change != "False":
+						print("Please input True or False.  ")
+						continue
+					else: 
+						change = bool(change)
+						teams[update_team][update_variable] = change
+						print("Successfully changed.  ")
+						continue
+				else:
+					teams[update_team][update_variable] = change
+					print("Successfully changed.  ")
+					continue
+			else:
+				print("Team " + str(update_team) + " was not found.  ")
+				continue
+		else:
+			print("Team " + str(update_team) + " was not found.  ")
+			continue
+
+	elif user_action == "add": 
+		new_team = input("Enter the number of the team you want to add. To return to the menu, enter 0. \n")
+		if not new_team.isnumeric():
+			print("Must be a number.  ")
+			continue
+		elif new_team == "0":
+			continue
+		else:
+			new_team = int(new_team)
+			teams[new_team] = {}
+			teams[new_team]["name"] = input("What is the team's name? \n")
+			teams[new_team]["programming language"] = input("What programming language does the team use? \n")
+			width = input("What is the width of the team's robot? \n")
+			if not width.isnumeric():
+				print("Width must be a number.  ")
+				continue
+			else: 
+				width = float(width)
+				teams[new_team]["width"] = width
+			length = input("What is the length of the team's robot? \n")
+			if not length.isnumeric():
+				print("Length must be a number.  ")
+				continue
+			else: 
+				length = float(width)
+				teams[new_team]["length"] = length
+			camera_vision = input("Does the team have a camera vision system? Input True or False. \n")
+			if camera_vision != "True" and camera_vision != "False":
+				print("Please follow directions.")
+				continue
+			else:
+				camera_vision = bool(camera_vision)
+				teams[new_team]["camera vision"] = camera_vision
+			drivetrain_motors = input("How many drivetrain motors does the robot have? \n")
+			if not drivetrain_motors.isnumeric(): 
+				print("Drivetrain motors must be a number.  ")
+				continue
+			else:
+				teams[new_team]["number of drivetrain motors"] = drivetrain_motors
+			print("Team added.  ")
+			continue
+	
+	elif user_action == "view": 
+		view_input = input("Which team's information would you like to view? To return to the menu, press 0. \n")
+		if not view_input.isnumeric():
+			print("Team must be a number. Returning	to menu... ")
+			continue
+
+		view_input = int(view_input)
+
+		if view_input == 0:
+			continue
+		elif view_input in teams: 
+			print(teams[view_input])
+			continue
+		else: 
+			print("Team " + str(view_input) + " has not been found.  ")
+			continue
+	elif user_action == "search": 
+		search_input = input("Which team would you like to search for? To return to the menu, enter 0. \n")
+		if search_input.isnumeric():
+			search_input = int(search_input)
+			if search_input == 0:
+				continue
+			elif search_input in teams.keys():
+				print(teams[search_input])
+			else:
+				print("Team does not exist.  ")
+				continue
+		else:
+			print("Invalid team. ")
+			continue
+	elif user_action == "quit":
+		break
+	else:
+		print("Invalid action.")
+		continue
\ No newline at end of file
diff --git a/ch_3_assign_kathy_li.py b/ch_3_assign_kathy_li.py
new file mode 100644
index 0000000..75279e3
--- /dev/null
+++ b/ch_3_assign_kathy_li.py
@@ -0,0 +1,139 @@
+teams = {}
+
+def master_action(): 
+	while True:
+		user_action = input("Welcome to the menu. Please select an action: add, remove, modify, view, search, or list. To quit, enter quit. \n")
+		if user_action == "list":
+			list_teams()
+		elif user_action == "remove":
+			remove_team()
+		elif user_action == "search":
+			search_team()
+		elif user_action == "add":
+			add_team()
+		elif user_action == "modify":
+			modify_team()
+		elif user_action == "view":
+			view_team()
+		elif user_action == "quit":
+			quit_program()
+
+def list_teams():
+    print(teams)
+
+def remove_team():
+	delete_team = input("Which team would you like to remove? \n")
+	if delete_team.isnumeric():
+		if delete_team in teams.keys():
+			teams.pop(delete_team)
+			print("Team " + str(delete_team) + " has been removed.   ")
+			return
+		else:
+			print("Team " + str(delete_team) + " has not been found.   ")
+			return
+	else: 
+		print("Team must be a number.")
+		return
+	
+def search_team():
+	search_input = input("Which team would you like to search for? \n")
+	if search_input.isnumeric(): 
+		if search_input in teams.keys():
+			print(teams[search_input])
+		else: 
+			print("Team not found.")
+	else:
+		print("Team must be a number.")
+
+def add_team():
+	new_team = input("Enter the number of the team you want to add. \n")
+	if new_team.isnumeric() == False:
+		print("Must be a number.   ")
+		return
+	else:
+		new_team = int(new_team)
+		teams[new_team] = {}
+		teams[new_team]["name"] = input("What is the team's name? \n")
+		
+		teams[new_team]["location"] = input("Where is the team located? \n")
+		
+		rookie_year = input("What is the team's rookie year? \n")
+		if not rookie_year.isnumeric():
+			print("Rookie year must be a number.   ")
+			return
+		else: 
+			rookie_year = int(rookie_year)
+			teams[new_team]["rookie year"] = rookie_year
+			
+		competed_in_2019 = input("Did they compete in 2019? Input True or False. \n")
+		if competed_in_2019 != "True" and competed_in_2019 != "False":
+			print("Please input True or False. ")
+			return
+		elif competed_in_2019 == "False":
+			competed_in_2019 = ""
+			competed_in_2019 = bool(competed_in_2019)
+			teams[new_team]["competed in 2019"] = competed_in_2019
+			print("Team added.")
+			return
+		else: 
+			competed_in_2019 = bool(competed_in_2019)
+			teams[new_team]["competed in 2019"] = competed_in_2019
+	
+		teams[new_team]["2019 competitions"] = input("What were their 2019 competitions? \n")
+		teams[new_team]["2019 awards"] = input("What awards did they receive in 2019? \n")
+		print("Team added.  ... ")
+
+
+def view_team():
+	view_input = input("Which team's information would you like to view? \n")
+	if not view_input.isnumeric():
+		print("Team must be a number. ")
+		return
+	view_input = int(view_input)
+	if view_input in teams: 
+		print(teams[view_input])
+	else: 
+		print("Team " + str(view_input) + " has not been found.   ")
+		return
+
+def modify_team(): 
+	update_team = input("Which team would you like to modify? To return the to the menu, enter 0. \n ")
+	if update_team.isnumeric():
+		if update_team in teams.keys():
+			update_variable = input("Which field would you like to modify: name, location, rookie year, compteted in 2019, 2019 competitions, or 2019 awards? \n")
+			if update_variable not in teams[update_team].keys():
+				print("There is no such field.   ")
+				return
+
+			change = input("Enter the new value. \n")
+			if update_variable == "rookie year": 
+				if not change.isnumeric():
+					print("Input is invalid.   ")
+					return
+				else:
+					teams[update_team][update_variable] = change
+					print("Successfully changed.   ")
+		
+			elif update_variable == "competed in 2019":
+				if change != "True" and change != "False":
+					print("Please input True or False. ")
+					return
+				else: 
+					change = bool(change)
+					teams[update_team][update_variable] = change
+					print("Successfully changed.   ")
+					return
+			else:
+				teams[update_team][update_variable] = change
+				print("Successfully changed.   ")
+		else:
+			print("Team " + str(update_team) + " was not found.   ")
+			return
+	else:
+		print("Team must be a number.")
+
+def quit_program():
+	##break
+	print("Use Ctrl-C to exit the program.")
+
+master_action()
\ No newline at end of file
diff --git a/ch_4_assign_kathy_li.py b/ch_4_assign_kathy_li.py
new file mode 100644
index 0000000..aea0a2f
--- /dev/null
+++ b/ch_4_assign_kathy_li.py
@@ -0,0 +1,68 @@
+import math
+
+class Point:
+    def __init__ (self, x, y):
+        self.x = x 
+        self.y = y
+    
+    def distance(self):
+       return math.sqrt(self.x**2 + self.y**2)
+
+class Point_3D(Point):
+    def __init__ (self, x, y, z):
+        super().__init__(x, y)
+        self.z = z
+
+    def distance(self):
+        return math.sqrt(self.x**2 + self.y**2 + self.z**2)
+
+while True:
+    x = input("What is the x-value of your point? \n" )
+
+    if x.isnumeric():
+        x = int(x)
+    else:
+        print("Invalid input.")
+        continue
+        
+    y = input("what is the y-value of your point? \n")
+    if y.isnumeric():
+        y = int(y)
+    else:
+        print("Invalid input.")
+        continue
+
+    point_a = Point(x, y) 
+    print("The distance from the origin is " + str(point_a.distance()))
+
+    x = input("What is the x-value of your point? \n" )
+    if x.isnumeric():
+        x = int(x)
+    else:
+        print("Invalid input.")
+        continue
+
+    y = input("what is the y-value of your point? \n")
+    if y.isnumeric():
+        y = int(y)
+    else:
+        print("Invalid input.")
+        continue
+
+    z = input("What is the z-value of your point? \n")
+    if z.isnumeric():
+        z = int(z)
+    else:
+        print("Invalid input.")
+        continue
+    point_b = Point_3D(x, y, z)
+    
+    print("The distance from the origin is " + str(point_b.distance()))
+
+    if point_a.distance() > point_b.distance():
+        print("The 2D point is further from the origin than the 3D point.")
+    elif point_b.distance() > point_a.distance():
+        print("The 3D point is further from the origin than the 2D point.")
+    elif point_a.distance() == point_b.distance():
+        print("The points are the same distance from the origin.")
+    break
\ No newline at end of file