#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int t;
  cin >> t;
  while (t--) {
    int n, m;
    cin >> n >> m;
    vector<int> deg(n, 0);
    rep(_, m) {
      int u, v;
      cin >> u >> v;
      --u, --v;
      deg[u]++, deg[v]++;
    }
    set<int> st(deg.begin(), deg.end());
    cout << (st.size() != n ? "Yes" : "No") << endl;
  }
  return 0;
}