t=int(input())
for _ in range(t):
    n,m=map(int,input().split())
    g=[0]*n
    for _ in range(m):
        u,v=map(int,input().split())
        g[u-1]+=1
        g[v-1]+=1
    from collections import Counter
    l=Counter(g)
    f=False
    for key,val in l.items():
        if val>=2:
            f=True
            break
    print('Yes'if f else 'No')