import sys
#sys.setrecursionlimit(10 ** 6)
INF = float('inf')
#10**20に変えるのもあり
MOD = 10**9 + 7
MOD2 = 998244353
def solve():
    def II(): return int(sys.stdin.readline())
    def LI(): return list(map(int, sys.stdin.readline().split()))
    def LC(): return list(input())
    def IC(): return [int(c) for c in input()]
    def MI(): return map(int, sys.stdin.readline().split())
    T = II()
    from collections import defaultdict
    for _ in range(T):
        N,M = MI()
        Graph = [[] for n in range(N + 1)]
        for m in range(M):
            u,v = MI()
            Graph[u].append(v)
            Graph[v].append(u)
        flag = True
        #print(Graph)
        Num = defaultdict(lambda: 0)
        for n in range(1,N+1):
            Num[len(Graph[n])] += 1
            if(Num[len(Graph[n])] >= 2):
                print("Yes")
                flag = False
                break
        if(flag):
            print("No")

    return
solve()