graph = []
color = []
answers = []
count_v = 0

def dfs(u):
    if color[u] == 2:
        return True
    color[u] = 1
    for v in graph[u]:
        if color[v] == 0:
            if not dfs(v):
                return False
        if color[v] == 1:
            return False
    color[u] = 2
    answers.append(u)
    return True


def top_sort():
    for i in range(1, count_v + 1):
        if not dfs(i):
            return [-1]
    return list(reversed(answers))


with open('input.txt', 'r') as fin:
    count_v, count_e = list(map(int, fin.readline().split()))
    graph = [[] for _ in range(count_v + 1)]
    color = [0 for _ in range(count_v + 1)]
    for _ in range(count_e):
        e1, e2 = list(map(int, fin.readline().split()))
        graph[e1].append(e2)

with open('output.txt', 'w') as fout:
    ans = top_sort()
    for idx, vertex in enumerate(ans):
        fout.write(str(vertex))
        if idx != len(ans) - 1:
            fout.write(' ')