#include <bits/stdc++.h>
using namespace std; 
struct t{
	int t1,t2;
}a[500010];
bool s(t b,t c){
	if(b.t1!=c.t1){
		return b.t1<c.t1;
	}
	return b.t2<c.t2;
}
int main(){
	int b,c,d,e,f=0,g=0,h=0,i,j,k;
	cin>>b;
	for(k=1;k<=b;k++){
		cin>>c>>d;
		for(i=1;i<=d;i++){
			cin>>a[i].t1>>a[i].t2;
		}
		sort(a+1,a+1+d,s);
		i=1;
		j=1;
		while(j<=d){
			while(a[j].t1>i){
				i++;
				cout<<endl;
			}
			cout<<a[j].t2<<' ';
			j++;
		}
		cout<<endl;
	}
	return 0;
}

B3613