#include <bits/stdc++.h>
#define int long long
//#define USE_FREOPEN
//#define MUL_TEST
#define FILENAME "circle"
using namespace std;
constexpr int N = 2e4 + 5;
vector<int> G[N],from[N];

void solve() {
	int n,m;
	cin >> n >> m;
	for (int i = 1; i <= m; i++) {
		int u,v;
		cin >> u >> v;
		G[u].push_back(v);
		G[v].push_back(u);
	}
	for (int v : G[1]) {
		for (int c : G[v]) {
			if (c != 1) {
				if (from[c].size() < 3) {
					from[c].push_back(v);
				}
			}
		}
	}
	for (int i = 2; i <= n; i++) {
		for (int c : G[i]) {
			for (int j : from[i]) {
				for (int k : from[c]) {
					if (j != c && j != k && k != i) {
						cout << "YES\n";
						return;
					}
				}
			}
		}
	}
	cout << "NO\n";
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr); cout.tie(nullptr);

	#ifdef USE_FREOPEN
		freopen(FILENAME ".in","r",stdin);
		freopen(FILENAME ".out","w",stdout);
	#endif
	int _ = 1;
	#ifdef MUL_TEST
		cin >> _;
	#endif
	while (_--)
		solve();
	_^=_;
	return 0^_^0;
}