#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)

signed main(){   
  int t;cin>>t;
  while(t--){
  int n,m;cin>>n>>m;
  vector<int>edge[n];  
  rep(i,m){
    int u,v;
    cin>>u>>v;
    u--;v--;
    edge[u].push_back(v);
    edge[v].push_back(u);
  }
  map<int,int>mp;
  rep(i,n){
    mp[edge[i].size()]++;
  }
    int flag=1;
  for(auto e:mp){
    if(e.second>1){
      cout<<"Yes"<<endl;
      flag=0;
      break;
    }
  }
    if(flag) cout<<"No"<<endl;
  }
    
  return 0;
}