from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

def answer():
    N,M = map(int,input().split())
    e = [[] for _ in range(N)]
    for _ in range(M):
        u,v = map(int,input().split())
        u -= 1
        v -= 1
        e[u].append(v)
        e[v].append(u)
    used = [0]*(N+1)
    for i in range(N):
        used[len(e[i])] += 1
        if used[len(e[i])]==2:
            print('Yes')
            return
    print('No')
for _ in range(int(input())):
    answer()