#include <bits/stdc++.h>
#include <string.h>
#define rep(i,n) for(int i = 0; i < n; i++)
#define srep(i,a,b) for(int i = a; i < b; i++)
#define all(A) (A).begin(),A.end()
#define MOD 1000000007
using namespace std;
using ll = long long;
using P = pair<int,int>;
using Graph = vector<vector<int>>;

int main(void){
	int t; cin >> t;
	rep(i,t){
		int n,m; cin >> n >> m;
		vector<int> C(n);
		rep(i,m){
			int a,b; cin >> a >> b;
			a--; b--;
			C[a]++; C[b]++;
		}
		map<int,int> M;
		rep(i,n) M[C[i]]++;
		bool ok = 0;
		for(auto& [k,v] : M) if(v >= 2) ok = 1;
		cout << (ok ? "Yes" : "No") << endl;
	}
}