using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[] NMi => ReadLine().Split().Select(c => int.Parse(c) - 1).ToArray();
    static int[][] NMap(int n) => Enumerable.Repeat(0, n).Select(_ => NMi).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var t = NN;
        var ans = new bool[t];
        for (var u = 0; u < t; ++u)
        {
            var c = NList;
            var (n, m) = (c[0], c[1]);
            var map = NMap(m);
            var count = new int[n];
            foreach (var edge in map)
            {
                ++count[edge[0]];
                ++count[edge[1]];
            }
            var clist = new int[n];
            for (var i = 0; i < n; ++i) ++clist[count[i]];
            for (var i = 0; i < n; ++i) if (clist[i] > 1)
            {
                ans[u] = true;
                break;
            }
        }
        WriteLine(string.Join("\n", ans.Select(f => f ? "Yes" : "No")));
    }
}