import bisect
import copy
import decimal
import fractions
import heapq
import itertools
import math
import random
import sys
import time
from collections import Counter,deque,defaultdict
from functools import lru_cache,reduce
from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max
def _heappush_max(heap,item):
    heap.append(item)
    heapq._siftdown_max(heap, 0, len(heap)-1)
def _heappushpop_max(heap, item):
    if heap and item < heap[0]:
        item, heap[0] = heap[0], item
        heapq._siftup_max(heap, 0)
    return item
from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines
write=sys.stdout.write

T=int(readline())
for t in range(T):
    N,M=map(int,readline().split())
    degree=[0]*N
    for m in range(M):
        u,v=map(int,readline().split())
        u-=1;v-=1
        degree[u]+=1
        degree[v]+=1
    if len(set(degree))==N:
        ans="No"
    else:
        ans="Yes"
    print(ans)