def solve():
    n,m = map(int,input().split())
    e = [0]*n
    for i in range(m):
        a,b = [int(x)-1 for x in input().split()]
        e[a] += 1
        e[b] += 1
    c = [0]*(n+1)
    for i in e:
        if c[i]:
            return "Yes"
        c[i] += 1
    return "No"
t = int(input())
for _ in range(t):
    print(solve())