/*
	嵌套变量重复
	特殊样例 0 1 2 n
	数组越界
	开long long
*/
#include<bits/stdc++.h>
using namespace std;
#define endl "\n"
#define int long long
#define pp(x) array<int,x>
using ull=unsigned long long;
using ll=long long;
using pii=pair<int,int>;
const int dx[]={0,0,1,-1,1,-1,1,-1};
const int dy[]={1,-1,0,0,1,-1,-1,1};
const int mod=998244353;
const int inf=0x3f3f3f3f;
const int INF=1e9+7;
const int maxn=1e6+100;
vector<int>v[maxn];
void solve()
{
	int n,m;
	cin>>n>>m;
	int tmp=(1+n-1)*(n-1)/2;
	for(int i=1;i<=n;i++)
		v[i].clear();
	for(int i=1;i<=m;i++){
		int x,y;
		cin>>x>>y;
		v[x].push_back(y);
		v[y].push_back(x);
	}
	if(n<=3||m==tmp)cout<<"YES"<<endl;
	else if(m!=tmp&&n!=4)cout<<"NO"<<endl;
	else if(n==4)
	{

		if(m==2&&v[1].size()==1&&v[2].size()==1&&v[3].size()==1&&v[4].size()==1)cout<<"YES"<<endl;
		else if(m==4&&v[1].size()==2&&v[2].size()==2&&v[3].size()==2&&v[4].size()==2)cout<<"YES"<<endl;
		else if(m==3&&(v[1].size()==0||v[2].size()==0||v[3].size()==0||v[4].size()==0))cout<<"YES"<<endl;

		else if(m==3&&v[1].size()==3&&v[2].size()==1&&v[3].size()==1&&v[4].size()==1)cout<<"YES"<<endl;
		else if(m==3&&v[1].size()==1&&v[2].size()==3&&v[3].size()==1&&v[4].size()==1)cout<<"YES"<<endl;
		else if(m==3&&v[1].size()==1&&v[2].size()==1&&v[3].size()==3&&v[4].size()==1)cout<<"YES"<<endl;
		else if(m==3&&v[1].size()==1&&v[2].size()==1&&v[3].size()==1&&v[4].size()==3)cout<<"YES"<<endl;

		else cout<<"NO"<<endl;
	}
	else cout<<"NO"<<endl;
}
signed main(){
 // freopen("C:\\Users\\tob\\Desktop\\P1000_0.in.txt","r",stdin);
 // freopen("C:\\Users\\tob\\Desktop\\P1000_0.out.txt","w",stdout);
	ios::sync_with_stdio(false);
	cin.tie(nullptr);cout.tie(nullptr);
	int __;cin>>__;
	while(__--)
		solve();
//  fclose(stdin);
//  fclose(stdout);
	return 0;
}