diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2baef9e..ce89870 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -3,3 +3,4 @@
 Please add your name.
 Yugesh Kothari
 Tanvi Nerkar
+Sarthak Rout
diff --git a/project1.py b/project1.py
index e66b77e..7cb2127 100644
--- a/project1.py
+++ b/project1.py
@@ -1,12 +1,22 @@
 def fib(number_for_fibonacci):
-	# Add code here
-	return #Fibonacci number
+	# By Sarthak Rout:
+	if number_for_fibonacci<=1 :
+		return 0
+	else :
+		return fib(number_for_fibonacci-1)+fib(number_for_fibonacci-2)
 
 
 def is_prime(number_to_check):
-    # Add code here
-    # comment added by new user
-    return #boolean value
+    # By Sarthak Rout:
+	if number_to_check==2 or number_to_check==3 :
+		return True
+	else :
+		k = int(sqrt(number_to_check)/6) ;
+		for i in range(1, k):
+			if number_to_check%(6*k-1)==0 or number_to_check%(6*k+1)==0:
+				return False
+
+		return True
 
 
 def reverse_string(string_to_be_reversed):
@@ -20,7 +30,8 @@ def reverse_string(string_to_be_reversed):
 
 
 #Take input for is_prime in variable b
-
+#By Sarthak Rout:
+b=int(input())
 print(is_prime(b))