#include <bits/stdc++.h>
#define pb emplace_back

using namespace std;

using LL = long long;


void solve()
{
	int n, m;
	cin >> n >> m;
	vector<int> deg(n + 1, 0), ea(m + 1, 0), eb(m + 1, 0);
	for(int i = 1; i <= m; ++i){
		int a, b;
		cin >> a >> b;
		ea[i] = a, eb[i] = b;
		++deg[a], ++deg[b];
	}
	
	
	if(n > 5){
		if(m != 1LL * (n * (n - 1)) / 2 && m)
			cout << "NO\n";
		else{
			cout << "YES\n";
		}
	}
	else{
		int ans = 0;
		map<vector<array<int, 2>>, int> mp;
		vector<int> per(n, 0);
		for(int i = 0; i < n; ++i)
			per[i] = i + 1;
		do{
			vector<array<int, 2>> edge;
			for(int j = 1; j <= m; ++j){
				int a = per[ea[j] - 1];
				int b = per[eb[j] - 1];
				if(a > b)
					swap(a, b);
				array<int, 2> t = {a, b};
				edge.pb(t);
			}
			sort(edge.begin(), edge.end());
			if(mp.count(edge))
				continue;
			mp[edge] = 1;
			++ans;
		}while(next_permutation(per.begin(), per.end()));
		
		if(ans <= n){
			cout << "YES\n";
		}
		else{
			cout << "NO\n";
		}
	}
}

int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	int T;
	cin >> T;

	
	while(T--){
		solve();
	}
	return 0;
}