#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


vector<int> List[1000];


int main() {

    int V,E,a,b;

    cin>>V>>E;

    for(int i = 1; i<=E; i++){
        cin>>a>>b;
        List[a].push_back(b);
    }
    for(int i = 0; i<V; i++){
        cout << i << " ";
        sort(List[i].begin(), List[i].end());
        for(int j=0; j<List[i].size(); j++){
            cout << List[i][j] << " ";
        }
        cout<<endl;
    }

    return 0;
}