edges = []
queue = []
l = []
num = int(input())
output = []
output1 = ""
Inbound_degree = [0 for _ in range(num)]
n = 10
while n != "":
    try:
        n = input()
        if n != "":
            n = list(map(int, n.split()))
            edges.append(n)
            Inbound_degree[n[1]] += 1
    except EOFError:
        break
for ind, i in enumerate(Inbound_degree):
    if i == 0:
        queue.append(ind)
    else:
        l.append(ind)

while len(queue) != 0:
    output1 += " ".join(map(str, Inbound_degree)) + "\n" + " ".join(map(str, queue)) + "\n"
    for i in edges:
        if i[0] == queue[0]:
            Inbound_degree[i[1]] -= 1

    for i in l:
        if Inbound_degree[i] == 0:
            queue.append(i)
            l.remove(i)

    el = queue.pop(0)
    output = [el] + output

bul = False
for i in Inbound_degree:
    if i != 0 and len(queue) == 0:
        bul = True
        break

print(output1[:len(output1) - 1])

if bul:
    print("None")
else:
    print(*output)