#!/usr/bin/env python3
from collections import defaultdict
import sys

MOD = 998244353

def main():
    T = int(input())

    for i in range(T):
        N, M = map(int, input().split())
        d = defaultdict(int)
        c = [0] * (2 * 10 ** 5 + 1)
        for _ in range(M):
            u, v = map(int, input().split())
            d[u] += 1
            d[v] += 1
        for k, dd in d.items():
            c[dd] += 1
            if c[dd] == 2:
                print("Yes")
                break
    return

    

if __name__ == '__main__':
    main()