class Tree:
    def __init__(self,data):
        self.children = []
        self.data = data

    def dfs(self):
        yield self
        if len(self.children) == 0:
            return
        for child in self.children:
            for c in child.dfs():
                yield c

    def bfs(self):
        yield self
        queue = list(self.children)
        while len(queue) > 0:
            first = queue[0]
            queue = queue[1:]
            queue.extend(first.children)
            yield first

if __name__ == "__main__":
    root = Tree(-1)
    root.children = [Tree(i) for i in range(5)]
    for i in range(5):
        root.children[i].children = [Tree(i*j) for j in range(3)]

    #-1,0,0,0,0...
    for node in root.dfs():
        print node.data

    print
    print

    #-1,0,1,2,3,4,0,0,0,0,1,2,0,2,4...
    for node in root.bfs():
        print node.data