def solve1():
n,m=list(map(int,input().split(" ")))
l1=[]
l2=[]
for i in range(m):
x,y=list(map(int,input().split(" ")))
l1.append(x)
l2.append(y)
for i in range(1,n+1):
for j in range(1,n+1):
if i not in l1 and j not in l1:
print("YES")
return
print("NO")
return ;
for i in range(int(input())):
solve1()
#include <bits/stdc++.h>
#define int long long
#define pb push_back
using namespace std;
void fast()
{
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output_new.txt", "w", stdout);
#endif
std::ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
void solve()
{
int n,m;
cin>>n>>m;
vector<int>temp;
for(int i=0;i<m;i++){
int x,y;
cin>>x>>y;
}
if(m==n)cout<<"NO"<<endl;
else cout<<"YES"<<endl;
}
main()
{
fast();
int t;
cin >> t;
while (t--)
solve();
}
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