#include <bits/stdc++.h>
using namespace std;

int main()
{
	int T;
	cin >> T;
	for( int i = 0; i < T; i++ ) {
		int N, M;
		cin >> N >> M;
		vector<int> deg( N );
		for( int j = 0; j < M; j++ ) {
			int u, v;
			cin >> u >> v;
			u--;
			v--;
			deg[u]++;
			deg[v]++;
		}
		string ans = "No";
		set<int> st;
		for( int j = 0; j < N; j++ ) {
			if( st.count( deg[j] ) ) {
				ans = "Yes";
				break;
			}
			st.insert( deg[j] );
		}
		cout << ans << endl;
	}
}