#include <bits/stdc++.h>
using namespace std;

vector<int> g[20000];
int color[20000];
int vis[20000][16];

bool dfs(int curr, int c, int s) {
	if (vis[curr][c]) return false;
	vis[curr][c] = true;
	if (curr != s) {
		if (c & 1 << color[curr]) return false;
		c |= 1 << color[curr];
	} else {
		if (c != 0) return c == 15;
	}

	for (int next : g[curr]) {
		if (dfs(next, c, s)) return true;
	}
	return false;
}

int main() {
	int n, m;
	cin >> n >> m;

	srand(time(NULL));

	for (int i = 0; i < m; i++) {
		int u, v;
		scanf("%d %d", &u, &v);
		u--; v--;
		g[u].push_back(v);
		g[v].push_back(u);
	}

	for (int i = 0; i < 50; i++) {
		memset(vis, false, sizeof(vis));

		for (int i = 0; i < n; i++) {
			color[i] = rand() % 4;
		}

		if (dfs(0, 0, 0)) {
			cout << "YES" << endl;
			return 0;
		}
	}
	cout << "NO" << endl;
}