#include<bits/stdc++.h>
using namespace std;
int h[500100];
struct Node {
	int e;
	int ne;
}l[500100];
int  m,n, idx = 0;
void add(int k, int x) {
	l[idx].e = x;
	l[idx].ne = h[k];
	h[k] = idx;
	idx++;
}int t;
int main() {
	cin >> t;
	while (t--) {
		cin >> n >> m;
		idx = 0;
		memset(h, -1, sizeof h);
		memset(l, 0, sizeof l);
		for (int i = 1; i <= m; i++) {
			int o, p;
			cin >> o >> p;
			add(o,p);
		}
		for (int i = 1; i <= n; i++) {
			for (int j = h[i]; j != -1; j = l[j].ne) {
				cout << l[j].e << ' ';
			}
			cout << endl;
		}
	}
	return 0;
}