#!/usr/bin/python
# encoding=utf8

from __future__ import print_function
# Author: OMKAR PATHAK

# We can use Python's dictionary for constructing the graph

class AdjacencyList(object):
 def __init__(self):
 self.List = {}

 def addEdge(self, fromVertex, toVertex):
 # check if vertex is already present
 if fromVertex in self.List.keys():
 self.List[fromVertex].append(toVertex)
 else:
 self.List[fromVertex] = [toVertex]

 def printList(self):
 for i in self.List:
 print((i,'->',' -> '.join([str(j) for j in self.List[i]])))

if __name__ == '__main__':
 al = AdjacencyList()
 al.addEdge(0, 1)
 al.addEdge(0, 4)
 al.addEdge(4, 1)
 al.addEdge(4, 3)
 al.addEdge(1, 0)
 al.addEdge(1, 4)
 al.addEdge(1, 3)
 al.addEdge(1, 2)
 al.addEdge(2, 3)
 al.addEdge(3, 4)

 al.printList()

 # OUTPUT:
 # 0 -> 1 -> 4
 # 1 -> 0 -> 4 -> 3 -> 2
 # 2 -> 3
 # 3 -> 4
 # 4 -> 1 -> 3