#include<bits/stdc++.h> using namespace std; vector<int> vec[10010]; int main (){ int n , m; cin >> n >> m; for (int i = 0;i < m;i++){ int a,b; cin >> a >> b; vec[a].push_back(b); } for(int i = 1;i <= n;i++){ for(int j = 0; j < vec[i].size(); j ++){ cout << vec[i][j] << " "; } cout << endl; } return 0; }

#include <iostream>
#include <vector>
using namespace std;
int m,x,y,n;
vector <int> v[10000];
int main(){
    cin>>n>>m;
    for(int i=0;i<m;i++){
        cin>>x>>y;
        v[x].push_back(y);
    }
    for(int i=0;i<=n;i++){
    	for(int j=0;j<v[i].size();j++){
    		cout<<v[i][j]<<" ";
		}
		cout<<endl;
	}
}