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

void solve() {
  size_t n, m;
  cin >> n >> m;

  vector<vector<int>> g(n);
  for (int i = 0; i < m; i++) {
    int u, v;
    cin >> u >> v;
    u--; v--;
    g[u].push_back(v);
    g[v].push_back(u);
  }

  set<size_t> st;
  for (const auto& edges : g) {
    if (st.find(edges.size()) != st.end()) {
      puts("Yes");
      return;
    }
    st.insert(edges.size());
  }
  puts("No");
}


int main() {
  int t;
  cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}