#include<iostream>
#include<stdio.h>
#include<math.h>
#include<iomanip>
#include<string>
#include<algorithm>
#include <cstdlib>
#include<stdlib.h>
#include<sstream>
#include<stack>
#include <climits>
#include<vector>
using namespace std;

const int N = 6e6;
vector<int> a[N];
long long t, n, m, x, y;

int main() 
{
	scanf_s("%llu",&t);
	for (long long i = 1; i <=t; i++)
	{
		scanf_s("%llu %llu", &n, &m);
		for (long long j = 1; j <= m; j++)
		{
			scanf_s("%llu %llu", &x, &y);
			a[x].push_back(y);
		}
		for (long long j = 1; j <= n; j++)
		{
			for (long long k = a[j].size()-1; k>=0; k--)
			{
				cout << a[j][k]<<" ";
			}
			cout << "\n";
		}
		for (long long j = 1; j <= n; j++)
		{
			a[j].clear();
		}
	}
	return 0;
}