#include<bits/stdc++.h>


using namespace std;
const int N=5e5+10; 
int u[N],v[N];
priority_queue<int,vector<int>,greater<int> >q[N];
bool cmp;
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int T;
	cin>>T;
	while(T--){
		int n,m;
		cin>>n>>m;
		memset(u,0,sizeof(u)); 
		memset(v,0,sizeof(v));
		for(int i=1;i<=m;++i){
			cin>>u[i]>>v[i];
			q[u[i]].push(v[i]);
		}
	
	for(int i=1;i<=n;++i){
			while(!q[i].empty()){
				cout<<q[i].top();
				cout<<" ";
				q[i].pop();
			}
			cout<<"\n";
	}
}
	return 0;
}