def solve():
    n,m = map(int,input().split())
    d = [0]*n
    for _ in range(m):
        u,v = map(int,input().split())
        d[u-1] += 1
        d[v-1] += 1
    r = [0]*n
    for i in d:
        if r[i]:
            return "Yes"
        else:
            r[i] += 1
    return "No"

for _ in range(int(input())):
    print(solve())