#include <bits/stdc++.h>
#include <assert.h>
using namespace std;
const long long MOD1 = 1000000007;
const long long MOD2 = 998244353;
#define logn long
#define lnog long
#define lgon long
#define itn int
typedef long long ll;
typedef pair<long long, long long> P;
const long long INF = 1e18;
void solve() {
    long long N, M; cin >> N >> M;
    vector<vector<long long>>G(N);
    for (long long i = 0; i < M; i++) {
        long long u, v; cin >> u >> v;
        u--; v--;
        G[u].push_back(v);
        G[v].push_back(u);
    }
    vector<long long>A(N + 1, 0);
    for (long long i = 0; i < N; i++) {
        if (A[G[i].size()]!=0){
            cout << "Yes" << endl;
            return;
        }
        A[G[i].size()]++;
    }
    cout << "No" << endl;
    return;
}
int main(){
    long logn T; cin >> T;
    for (long long i = 0; i < T; i++) {
        solve();
    }
}