#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001

int main(){
	
	int _t;
	cin>>_t;
	
	rep(_,_t){
		int n,m;
		cin>>n>>m;
		
		vector<int> d(n,0);
		rep(i,m){
			int a,b;
			cin>>a>>b;
			d[a-1]++;
			d[b-1]++;
		}
		
		set<int> S;
		rep(i,n)S.insert(d[i]);
		
		if(S.size()==n)cout<<"No"<<endl;
		else cout<<"Yes"<<endl;
	}
	
    return 0;
}