#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;
	}
}