#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using vi = vector<int>;
using ll = int64_t;
using pii = pair<int, int>;
using vpii = vector<pii>;

int find_ans(const int n, const vpii& e) {
	vi d(n);
	for (pii f : e) {
		++d[f.first];
		++d[f.second];
	}
	int k0 = 0, k1 = 0, m0 = 0, m1 = 0;
	for (int i : d) {
		if (i == 0) ++k0;
		if (i == 1) ++k1;
		if (i == n - 1) ++m0;
		if (i == n - 2) ++m1;
	}
	if (k0 + m1 >= n) return true;
	if (m0 + k1 >= n) return true;
	if (k0 || m0) return false;
	return n == 4;
}
void solve_test() {
	int n, m;
	cin >> n >> m;
	vpii e(m);
	for (int i = 0; i < m; ++i) {
		cin >> e[i].first >> e[i].second;
		--e[i].first; --e[i].second;
	}
	cout << (find_ans(n, e) ? "YES\n" : "NO\n");
}
void solve_tests() {
	int t;
	cin >> t;
	for (int i = 0; i < t; ++i) {
		solve_test();
	}
}
int main() {
#ifdef ONPC
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	solve_tests();
}