class Node:
    def __init__(self, name = None, color = 'white', successors = []):
        self.name = name
        self.color = color
        self.successors = successors

def top_order(G):
    L = []
    nameList = []
    for ele in G:
        if ele.color == 'white':
            L.extend(dfs(G,ele))
    if -1 not in L:
        L.reverse()
##        nameList = list(map(lambda x: x.name, L))
        for knoten in L:
            nameList.append(knoten.name)
        return nameList
    else:
        return [-1]
    
def dfs(G, r):
    besuchtList = []
    stack = []
    r.color = 'grey'
    stack.append(r)
    while stack != []:
        v = stack[-1]
        a = False
        for n in v.successors:
            if n.color == 'grey':
                return [-1]
        for n in v.successors:
            if n.color == 'white':
                n.color = 'grey'
                stack.append(n)
                a = True
                break
        if not a:
            v.color = 'bleak'
            besuchtList.append(stack.pop())
    return besuchtList

A = Node("内裤",'white',[])
B = Node("秋裤",'white',[])
C = Node("牛仔裤",'white',[])
D = Node("袜子",'white',[])
E = Node("鞋子",'white',[])
F = Node("秋衣",'white',[])
G = Node("外套",'white',[])
A.successors = [B]
B.successors = [C]
C.successors = [E]
D.successors = [E]
F.successors = [G]

G = [E,C,D,B,A,G,F]
print(top_order(G))