#include<bits/stdc++.h>
using namespace std;
int m,n;
vector<int> nextpoints[10086];
int main()
{
cin>>n>>m;
for(int i=0,u,v;i<m;i++){
	cin>>u>>v;
	nextpoints[u].push_back(v);
}
for(int i=1;i<=m;i++){
	for(auto v:nextpoints[1]){
	cout<<v<<" ";
}
cout<<endl;
}

return 0;
}