from collections import Counter

T = int(input())
for t in range(T):
    N, M = map(int, input().split())
    deg = [0]*N
    for i in range(M):
        u, v = map(int, input().split())
        deg[u-1] += 1
        deg[v-1] += 1
    counted = Counter(deg)
    mx = max(counted.values())
    if mx > 1:
        print('Yes')
    else:
        print('No')