#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> d(N, 0);
    for (int j = 0; j < M; j++){
      int u, v;
      cin >> u >> v;
      u--;
      v--;
      d[u]++;
      d[v]++;
    }
    vector<bool> used(N + 1, false);
    bool ok = false;
    for (int j = 0; j < N; j++){
      if (used[d[j]]){
        ok = true;
      }
      used[d[j]] = true;
    }
    if (ok){
      cout << "Yes" << endl;
    } else {
      cout << "No" << endl;
    }
  }
}