import collections
n, m = map(int, input().split())
e = collections.defaultdict(set)
di = [0 for i in range(n+1)]
di[0] = -1

for i in range(m):
    a, b = map(int, input().split())
    if b not in e[a]: ## 建边链表
        e[a].add(b)
        di[b] += 1

q, res = [], []   ## 把入度为0的入队
for i in range(n+1):
    if di[i] == 0:
        q.append(i)

while len(q) != 0:
    cur = q.pop()
    res.append(cur)
    for v in e[cur]:   ## 更新入度，并把入度为0的放入队列
        di[v] -= 1
        if di[v] == 0:
            q.append(v)

if len(res) == n:
    print(" ".join(map(str, res)))
else:
    print(-1)