diff --git a/graph/bfs.py b/graph/bfs.py
index 750953c..57f29b4 100644
--- a/graph/bfs.py
+++ b/graph/bfs.py
@@ -1,13 +1,16 @@
 __author__ = 'Minsuk Heo'
 
-vertexList = ['A', 'B', 'C', 'D', 'E', 'F', 'G']
-edgeList = [(0,1), (1,2), (1,3), (3,4), (4,5), (1,6)]
+vertexList = ["0", "1", "2", "3", "4", "5", "6"]
+edgeList = [(0, 1), (0, 2), (1, 0), (1, 3), (2, 0), (2, 4), \
+            (2, 5), (3, 1), (4,2), (4, 6), (5,2), (6,4)]
 graphs = (vertexList, edgeList)
 
 def bfs(graph, start):
+    
     vertexList, edgeList = graph
     visitedList = []
     queue = [start]
+
     adjacencyList = [[] for vertex in vertexList]
 
     # fill adjacencyList from graph
@@ -19,9 +22,8 @@ def bfs(graph, start):
         current = queue.pop()
         for neighbor in adjacencyList[current]:
             if not neighbor in visitedList:
-                queue.insert(0,neighbor)
+                queue.insert(0, neighbor)
         visitedList.append(current)
     return visitedList
-
-print(bfs(graphs, 0))
-
+    
+print (bfs(graphs, 0))