#include "bits/stdc++.h"
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
static const int INF = 0x3f3f3f3f; static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> static void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> static void amax(T &x, U y) { if(x < y) x = y; }


int main() {
	int N; int M;
	while(~scanf("%d%d", &N, &M)) {
		vector<vector<int> > g(N);
		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);
		}
		default_random_engine re{ random_device{}() };
		uniform_int_distribution<int> dist(0, 3);
		bool ans = false;
		rep(k, 200) {
			vector<int> col(N, -1);
			reu(i, 1, N)
				col[i] = dist(re);
			vector<vector<bool>> dp(1 << 4, vector<bool>(N));
			dp[0][0] = true;
			rep(s, (1 << 4) - 1) rep(i, N) if(dp[s][i]) {
				for(int j : g[i]) if(j != 0) {
					int t = s | 1 << col[j];
					if(s < t)
						dp[t][j] = true;
				}
			}
			rep(i, N) if(dp.back()[i]) {
				for(int j : g[i]) if(j == 0)
					ans = true;
			}
		}
		puts(ans ? "YES" : "NO");
	}
	return 0;
}