#define _CRT_SECURE_NO_WARNINGS // #pragma warning(disable:4996)
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <string>
#include <queue>
#include <functional>
#include <sstream>
#include <cmath>
#include <set>
#include <map>
#include <unordered_set>
using namespace std; 

#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define pb push_back
#define mp(a,b) make_pair(a,b)
#define all(a) a.begin(),a.end()
#define len(x) ((int)(x).size())
#define tmax(a,b,c) max((a),max((b),(c)))
#define tmin(a,b,c) min((a),min((b),(c)))
#define debug(x) cerr << #x << " is " << x << endl;

typedef pair<int, int> Pii;
typedef vector<int> Vi;
typedef vector<vector<int> > VVi;
typedef long long ll;
const int inf = 2e9;
const int mod = 1e9 + 7;
const long double eps = 1e-10;

int N, M;
int V1[50001];
int V2[50001];
Vi A[50001];
Vi B[50001];

int main()
{
	cin >> N >> M;
	rep(i,0,M) {
		scanf("%d %d", &V1[i], &V2[i]);
		V1[i]--; V2[i]--;
		A[V2[i]].pb(V1[i]);
		A[V1[i]].pb(V2[i]);
	}

	for (auto a: A[0]) {
		for (auto b: A[a]) {
			if (b) B[b].pb(a);
		}
	}

	rep(i, 0, M) {
		int l = V1[i];
		int r = V2[i];
		if (B[l].size() && B[r].size()) {
			if (B[l].size() == 1 && B[r].size() == 1) {
				if (B[l][0] != B[r][0] && B[l][0] != r) {
					cout << "YES" << endl;
					return 0;
				}
			}
			else if (B[l].size() >= 1 && B[r].size() >= 1 && max(B[l].size(), B[r].size()) >= 2) {
				cout << "YES" << endl;
				return 0;
			}
		}
	}
	cout << "NO" << endl;
	return 0;
}