/* -*- coding: utf-8 -*-
 *
 * 1563.cc:  No.1563 Same Degree - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 200000;

/* typedef */

/* global variables */

int dgs[MAX_N], cs[MAX_N];

/* subroutines */

/* main */

int main() {
  int tn;
  scanf("%d", &tn);

  while (tn--) {
    int n, m;
    scanf("%d%d", &n, &m);

    fill(dgs, dgs + n, 0);
    for (int i = 0; i < m; i++) {
      int u, v;
      scanf("%d%d", &u, &v);
      u--, v--;
      dgs[u]++, dgs[v]++;
    }

    bool ok = false;
    fill(cs, cs + n, 0);
    for (int i = 0; i < n; i++)
      if (++cs[dgs[i]] > 1) {
	ok = true;
	break;
      }

    if (ok) puts("Yes");
    else puts("No");
  }
  return 0;
}