#include <bits/stdc++.h>
using namespace std;
const int N =1e3;

int main(){
	int n,m;
	cin>>n>>m;
	vector<vector<int>> a(N, vector<int>(0));
	while(m--){
		int x,y;
		cin>>x>>y;
		a[x-1].push_back(y);//也是从0开始的
	}
	for(int i = 0 ; i < n ; i++){
		sort(a[i].begin(),a[i].end());
	}
	for(int i = 0 ; i < n ; i++){
    	cout<<a[i].size()<<" ";
        for(int j = 0 ; j < a[i].size(); j++){
            cout<<a[i][j]<<" ";
        }
        cout<<endl;
    }
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

struct loc{
    vector<int> num;
};

int main(){
    int n,m,x,y;
    cin>>n>>m;
    loc a[n];
    for(int i = 0 ; i < m ; i++){
    	cin>>x>>y;
    	a[x-1].num.push_back(y);
	}
	for(int i = 0 ; i < n ; i++){
		sort(a[i].num.begin(),a[i].num.end());
	}
    for(int i = 0 ; i < n ; i++){
    	int size = a[i].num.size();
    	cout<<size<<" ";
        for(int j = 0 ; j < size; j++){
            cout<<(a[i].num)[j]<<" ";
        }
        cout<<endl;
    }
    return 0;
}

#include <iostream>

#include <algorithm>

#include <vector>

#include <stack>

#include <set>

#include <queue>

#include <map>

typedeflonglongll;

using****namespacestd;

voidsolve14(){

** **map<ll,vector<ll>> s;

** **ll n,m;

** **s[0].push_back(0);

** **cin>>n>>m;

** **for (ll i=0; i<m; i++) {

** **ll j,l;

** **cin>>j>>l;

** **s[j].push_back(l);

** **}

** **for (ll i=1; i<=n; i++) {

** **cout<<s[i].size()<<" ";

** **sort(s[i].begin(),s[i].end());

** **for (ll j=0;j<s[i].size() ; j++) {

** **cout<<s[i][j]<<" ";

** **}

** **cout<<endl;

** **}

---

}

int main(){

** **int t=1;

** **//cin>>t;

** **while(t>0){

** **solve14();

** **t--;

** **}

** **return 0;

}

//用了map