#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

void solve(){
    int n,m;cin>>n>>m;
    vector<int> A(n);
    for(int i = 0; m > i; i++){
        int x,y;cin>>x>>y;
        A[--x]++;A[--y]++;
    }
    sort(A.begin(),A.end());
    for(int i = 0; n-1 > i; i++){
        if(A[i] == A[i+1]){
            cout << "Yes" << endl;
            return;
        }
    }
    cout << "No" << endl;
}

int main(){
    int n;cin>>n;
    for(int i = 0; n > i; i++){
        solve();
    }
}