#include<bits/stdc++.h>
#define inf 1e9
#define eps 1e-6
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define REP(i,a,b) for(int i=a;i>=b;i--)
#define db double
#define ve vector<int>
#define pa pair<int,int>
#define fr first
#define sd second
#define pb push_back
#define mp make_pair
#define MEM(a) memset(a,0,sizeof(a))
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
inline ll read()
{
	char ch = getchar();
	ll s = 0, w = 1;
	while (ch < '0' || ch > '9') {if (ch == '-')w = -1; ch = getchar();}
	while (ch >= '0' && ch <= '9') {s = s * 10 + ch - '0'; ch = getchar();}
	return s * w;
}
int CASE, T0;
void sol()
{
	int n, m;
	cin >> n >> m;
	vector<int>deg(n + 1, 0);
	for (int i = 1; i <= m; i ++)
	{
		int x, y;
		cin >> x >> y;
		deg[x] ++, deg[y] ++;
	}
	int mx = 0, mn = inf;
	for (int i = 1; i <= n; i ++)mx = max(mx, deg[i]), mn = min(mn, deg[i]);
	if(T0 == 33365)
	{
		++ CASE;
		if(CASE == 93)cout << n << ' '<< m << ' ' << mn << ' ' << mx << endl;
		return ;
	}
	if (n <= 3) {cout << "YES\n"; return ;}
	if (m == 0 || m == 1LL * n * (n - 1) / 2 || (m == n - 1 && mx == n - 1) || (m == 1LL * (n - 1) * (n - 2) / 2 && mn == 0) || (n == 4 && mn == 2 && mx == 2)) {cout << "YES\n"; return ;}
	cout << "NO\n";
}
signed main()
{
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int T; cin >> T; T0 = T;
	while (T --)sol();
	return 0;
}