#include <bits/stdc++.h>

using namespace std;
const int N = 2e5 + 5;

int n, m;
vector<int> e[N];

unordered_set<int> C[N];
bool solve() {
	for (int i: e[1])
		for (int j: e[i]) {
			if (j == 1)
				continue;
			C[j].insert(i);
		}

	for (int i = 1; i <= n; i++) 
		for (int j: e[i]) {
			if (j < i)
				continue;
			if (i == 1 || j == 1)
				continue;
	
			int num_i = C[i].size();
			if (C[i].count(j))
				num_i--;
			int num_j = C[j].size();
			if (C[j].count(i))
				num_j--;
	
			if (num_i == 1 && num_j == 1) {
				int a;
				for (int k : C[i])
					if (k != i && k != j)
						a = k;
				int b;
				for (int k : C[j])
					if (k != i && k != j)
						b = k;
				if (a != b)
					return true;
			}
	
			if (1 <= num_i && 1 <= num_j) {
				int m = max(num_i, num_j);
				if (2 <= m)
					return true;
			}
		}

	return false;
}

int main() {
//	freopen("1.in", "r", stdin);
	
	cin >> n >> m;
	for (int i = 1, u, v; i <= m; i++) {
		cin >> u >> v;
		e[u].push_back(v);
		e[v].push_back(u);
	}
	if (solve())
		puts("YES");
	else
		puts("NO");
	return 0;
}