from collections import Counter
for _ in range(int(input())):
    n, m = map(int, input().split())
    deg = [0] * n
    for _ in range(m):
        u, v = map(int, input().split())
        deg[u - 1] += 1
        deg[v - 1] += 1
    print('Yes' if any(v >= 2 for k, v in Counter(deg).items()) else 'No')