#include<bits/stdc++.h> #include<vector> using namespace std; vector<int> a[100000]; int main(){ int n,m,x,y; cin>>n>>m; for(int i=0;i<m;i++){ cin>>x>>y; a[x-1].push_back(y); } for(int i=0;i<n;i++){ cout<<a[i].size()<<" "; sort(a[i].begin(),a[i].end()); for(int j=0;j<a[i].size();j++){ cout<<a[i][j]<<" "; } cout<<endl; } }