#include <bits/stdc++.h>
template<class T> inline bool chmin(T&a, T b){if(a > b){a = b; return true;}else{return false;}}
template<class T> inline bool chmax(T&a, T b){if(a < b){a = b; return true;}else{return false;}}
#define ll long long
#define double long double
#define rep(i,n) for(int i=0;i<(n);i++)
#define REP(i,n) for(int i=1;i<=(n);i++)
#define mod (ll)(1e9+7)
#define inf (ll)(3e18+7)
#define eps (double)(1e-9)
#define pi (double) acos(-1)
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
using namespace std;

void solve(){
    int n, m;
    cin >> n >> m;
    vector<int> d(n);
    rep(i, m){
        int a, b;
        cin >> a >> b;
        a--; b--;
        d[a]++; d[b]++;
    }
    sort(all(d));
    bool ans = false;
    rep(i, n-1)if(d[i+1] == d[i])ans = true;
    cout << (ans ? "Yes" : "No") << endl;
}

int main(){
    int t;
    cin >> t;
    while(t--)solve();
}