#include <iostream>
#include <algorithm>
using namespace std;

int T;

int main() {
	cin >> T;
	while (T--) {
		int n, m;
		cin >> n >> m;
		
		int cnt[100000] = {0};
		for (int i = 0; i < m; i++) {
			int u, v;
			cin >> u >> v;
			u--; v--;
			cnt[u]++; cnt[v]++;
		}
		
		sort(cnt, cnt + n);
		
		bool flag = false;
		for (int i = 0; i < n - 1; i++) {
			if (cnt[i] == cnt[i + 1]) {
				cout << "Yes" << endl;
				flag = true;
				break;
			}
		}
		if (!flag) {
			cout << "No" << endl;
		}
	}
	return 0;
}