class Hawwary:
    def __init__(self):
        self.graph=[]


    def AddNode(self):
        self.graph.append([])


    def AddEgde(self,edge):
        self.graph[edge[0]].append(edge[1])


    def DeletNode(self,key):
        del self.graph[key]
        for v in self.graph:
            for e in v:
                if key==e:
                   del self.graph[v][e]

    def DeleteEdge(self,edge):
        del self.graph[edge[0]][edge[1]]

    def itSuccessor(self,key):
        return self.graph[key]