import std.stdio;
import std.algorithm;
import std.typecons;
import std.string;
import std.array;
import std.conv;
import std.container;

void main() {
    int N, M;
    scanf("%d %d\n", &N, &M);
    alias E = Tuple!(int, int);
    bool[E] es;
    E[] es1;
    bool[int] zero_n;
    auto G = new int[][](N);
    foreach (i; 0 .. M) {
        int a, b;
        scanf("%d %d\n", &a, &b);
        a--; b--;
        G[a] ~= b;
        G[b] ~= a;
        if (a > b) swap(a, b);
        if (a == 0) zero_n[b] = true;
        else es1 ~= E(a, b);
        es[E(a, b)] = true;
    }

    bool f(int a, int b) {
        if (a > b) swap(a, b);
        return E(a, b) in es ? true : false;
    }

    const int INF = int.max / 2;

    foreach (e; es1) {
        int a = -1, b = -1;
        int c = 0;
        foreach (i; G[e[0]]) {
            if (i !in zero_n) continue;
            if (i == e[1]) continue;
            if (f(e[0], i)) {
                if (a < 0) a = i;
                else a = INF;
            }
        }
        foreach (i; G[e[1]]) {
            if (i !in zero_n) continue;
            if (i == e[0]) continue;
            if (f(e[1], i)) {
                if (b < 0) b = i;
                else b = INF;
            }
        }

        if (a >= 0 && b >= 0) {
            if ( (a == INF || b == INF) || (a != b) ) {
                writeln("YES");
                return;
            }
        }
    }
    writeln("NO");

}