def topologicSort(graph): # граф ориентированный, в виде словаря, нападобии списка смежности
    resultArr = []
    visited = []
    while len(graph) != len(visited):
        for s1 in graph.keys():
            s1 = int(s1)
            for s2 in graph.values():
                if s1 in s2 or s1 in visited:
                    break
            else:
                resultArr.append(s1)
                visited.append(s1)
                if len(visited) == len(graph):
                    resultArr.extend(graph[s1])
                graph[s1] = [s1]
                break
    return resultArr
n, m = [int(i) for i in input().split()] # n - кол-во вершин, m - кол-во ребер
test_graph = {}
for i in range(m):
    first, last = [int(i) for i in input().split()]
    if first not in test_graph:
        test_graph[first] = []
    test_graph[first].append(last)
arr = sorted(test_graph)
arr.reverse()
graph = {}
for i in arr:
    graph[i] = test_graph[i]
print(graph)
print(topologicSort(graph))