#include <iostream>
#include <utility>
#include <vector>
using namespace std;

typedef pair<int, int> Edge;

const int MAX_N = 3 * 10000;
const int MAX_M = 5 * 10000;

bool is_connected_one[MAX_N];
Edge edges[MAX_M];
vector<int> connected_target_nodes[MAX_N];

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N, M;
    cin >> N >> M;

    for (auto i = 0; i < M; i++) {
        int a, b;
        cin >> a >> b;
        edges[i] = Edge(a - 1, b - 1);

        if (a == 1) is_connected_one[b - 1] = true;
        if (b == 1) is_connected_one[a - 1] = true;
    }

    for (auto i = 0; i < M; i++) {
        auto v1 = edges[i].first, v2 = edges[i].second;
        if (is_connected_one[v1]) {
            connected_target_nodes[v2].push_back(v1);
        }
        if (is_connected_one[v2]) {
            connected_target_nodes[v1].push_back(v2);
        }
    }

    for (auto i = 0; i < M; i++) {
        auto v1 = edges[i].first, v2 = edges[i].second;
        if (v1 == 0 || v2 == 0) continue;
        // v1, v2は除いたとき、どっちも1以上で
        // かつ (どちらかが2 もしくは どちらも違う頂点を指す)
        auto v1_num = connected_target_nodes[v1].size(),
             v2_num = connected_target_nodes[v2].size();
        if (is_connected_one[v2]) v1_num--;
        if (is_connected_one[v1]) v2_num--;
        if (v1_num < 1 || v2_num < 1) continue;

        if (v1_num >= 2 || v2_num >= 2) {
            cout << "YES" << endl;
            return 0;
        } else {
            int v1_have_node, v2_have_node;
            for (auto node : connected_target_nodes[v1]) {
                if (node != v2) {
                    v1_have_node = node;
                    break;
                }
            }
            for (auto node : connected_target_nodes[v2]) {
                if (node != v1) {
                    v2_have_node = node;
                    break;
                }
            }
            if (v1_have_node != v2_have_node) {
                cout << "YES" << endl;
                return 0;
            }
        }
    }
    cout << "NO" << endl;

    return 0;
}