#include <iostream>
#include <vector>
#include <stack>
//#include <bits/stdc++.h>
using namespace std;
int n, m;
vector<int>graph[3005];
vector<int>rev_graph[3005];
bool visited[3005];
stack<int>s;
void dfs(int node){

visited[node]=true;
for(int i=0; i<graph[node].size(); i++){
    int sosed=graph[node][i];
    if(!visited[sosed]){
        dfs(sosed);
    }

}
    s.push(node);
}
void rev_dfs(int node){
visited[node]=true;
cout<<node<<" ";
for(int i=0; i<rev_graph[node].size(); i++){
    int rev_sosed=rev_graph[node][i];
    if(!visited[rev_sosed]){
        rev_dfs(rev_sosed);
    }
}
}


int main()
{
    cin>>n>>m;
    for(int i=0; i<m; i++){
        int a, b;
        cin>>a>>b;
        a--;
        b--;
        graph[a].push_back(b);
        rev_graph[b].push_back(a);
    }
    memset(visited, false, sizeof visited);

    for(int i=0; i<n; i++){
        if(!visited[i]){
            dfs(i);
        }
    }
    memset(visited, false, sizeof visited);
    while(!s.empty()){
        int node=s.top();
//        cout << node << endl;
        if(!visited[node]){
            rev_dfs(node);
            cout<<endl;
        }
        s.pop();
    }
    return 0;
}