from __future__ import annotations






def    __lowerCamelCase	(		lowerCAmelCase__			):
       global graph, reversed_graph, scc, component, visit, stack
       if visit[u]:
              return
       lowerCAmelCase__  			=      True
       for v in graph[u]:
              dfs(lowerCAmelCase__			)
       stack.append(lowerCAmelCase__			)






def    __lowerCamelCase	(		lowerCAmelCase__			):
       global graph, reversed_graph, scc, component, visit, stack
       if visit[u]:
              return
       lowerCAmelCase__  			=      True
       component.append(lowerCAmelCase__			)
       for v in reversed_graph[u]:
              dfsa(lowerCAmelCase__			)






def    __lowerCamelCase	(		):
       global graph, reversed_graph, scc, component, visit, stack
       for i in range(lowerCAmelCase__			):
              dfs(lowerCAmelCase__			)
       lowerCAmelCase__  			=      [False] * n
       for i in stack[::-1]:
              if visit[i]:
                     continue
              lowerCAmelCase__  			=      []
              dfsa(lowerCAmelCase__			)
              scc.append(lowerCAmelCase__			)
       return scc


if __name__ == "__main__":
    # n - no of nodes, m - no of edges
    lowerCAmelCase__		,	lowerCAmelCase__					=				list(map(int, input().strip().split()))

    lowerCAmelCase__					=				[[] for _ in range(n)]  # graph
    lowerCAmelCase__					=				[[] for i in range(n)]  # reversed graph
    # input graph data (edges)
    for _ in range(m):
        lowerCAmelCase__		,	lowerCAmelCase__					=				list(map(int, input().strip().split()))
        graph[u].append(v)
        reversed_graph[v].append(u)

    lowerCAmelCase__					=				[]
    lowerCAmelCase__					=				[False] * n
    lowerCAmelCase__					=				[]
    lowerCAmelCase__					=				[]
    print(kosaraju())

from __future__ import annotations






def    __lowerCamelCase	(		lowerCAmelCase__			):
       global graph, reversed_graph, scc, component, visit, stack
       if visit[u]:
              return
       lowerCAmelCase__  			=      True
       for v in graph[u]:
              dfs(lowerCAmelCase__			)
       stack.append(lowerCAmelCase__			)






def    __lowerCamelCase	(		lowerCAmelCase__			):
       global graph, reversed_graph, scc, component, visit, stack
       if visit[u]:
              return
       lowerCAmelCase__  			=      True
       component.append(lowerCAmelCase__			)
       for v in reversed_graph[u]:
              dfsa(lowerCAmelCase__			)






def    __lowerCamelCase	(		):
       global graph, reversed_graph, scc, component, visit, stack
       for i in range(lowerCAmelCase__			):
              dfs(lowerCAmelCase__			)
       lowerCAmelCase__  			=      [False] * n
       for i in stack[::-1]:
              if visit[i]:
                     continue
              lowerCAmelCase__  			=      []
              dfsa(lowerCAmelCase__			)
              scc.append(lowerCAmelCase__			)
       return scc


if __name__ == "__main__":
    # n - no of nodes, m - no of edges
    lowerCAmelCase__		,	lowerCAmelCase__					=				list(map(int, input().strip().split()))

    lowerCAmelCase__					=				[[] for _ in range(n)]  # graph
    lowerCAmelCase__					=				[[] for i in range(n)]  # reversed graph
    # input graph data (edges)
    for _ in range(m):
        lowerCAmelCase__		,	lowerCAmelCase__					=				list(map(int, input().strip().split()))
        graph[u].append(v)
        reversed_graph[v].append(u)

    lowerCAmelCase__					=				[]
    lowerCAmelCase__					=				[False] * n
    lowerCAmelCase__					=				[]
    lowerCAmelCase__					=				[]
    print(kosaraju())
