#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (ll i=(ll)N-1; i>=0; i--)
#define popcount __builtin_popcount

const ll LLINF = pow(2,61)-1;
const ll INF = pow(2,30)-1;

ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

int main() {
  ll T; cin >> T;
  rep(_,T) {
    ll N, M; cin >> N >> M;
    ll zi[N] = {}; rep(i,M) { ll u, v; cin >> u >> v; zi[u-1]++; zi[v-1]++; }
    map<ll, ll> m; rep(i,N) m[zi[i]]++;
    string result = "No"; for (auto x: m) if (x.second>=2) result = "Yes";
    cout << result << endl;
  }
  return 0;
}