#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <cmath>
#include <iomanip>
#include <stack>
#include <queue>
#include <numeric>
#include <map>
#include <unordered_map>
#include <set>
#include <fstream>
#include <chrono>
#include <random>
#include <bitset>
//#include <atcoder/all>
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) ((int)(x).size())
#define pb push_back
using ll = long long;
using namespace std;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
ll gcd(ll a, ll b) {return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) {return a/gcd(a,b)*b;}

int main(){
  int T; cin >> T;
  while(T--){
    int N, M; cin >> N >> M;
    vector<int> cnt(N,0);
    rep(i,M){
      int a,b; cin >> a >> b; a--; b--; cnt[a]++; cnt[b]++;
    }
    sort(all(cnt));
    int ok = 0;
    rep(i,N-1){
      if(cnt[i]==cnt[i+1]){
        ok=1;break;
      }
    }
    if(ok) cout << "Yes" << endl;
    else cout << "No" << endl;
  }
  return 0;
}