from collections import Counter

T=int(input())
for tests in range(T):
    N,M=map(int,input().split())

    D=[0]*N
    for i in range(M):
        x,y=map(int,input().split())
        D[x-1]+=1
        D[y-1]+=1

    C=Counter(D)

    flag=0
    for c in C:
        if C[c]>=2:
            flag=1

    if flag==1:
        print("Yes")
    else:
        print("No")