import collections
T = int(input())
for _ in range(T):
    N,M = map(int, input().split())
    L = [0]*N
    for _ in range(M):
        a,b = map(int, input().split())
        L[a-1]+=1
        L[b-1]+=1
    C = collections.Counter(L)
    for v in C.values():
        if v>=2:
            print('Yes')
            break
    else:
        print('No')