#include <bits/stdc++.h>
using namespace std;
using ll = long long;

unsigned long long xor64(){
    static unsigned long long x = 88172645463325252LL;
    x ^= (x << 13);
    x ^= (x >> 7);
    return (x ^= (x << 17));
}

//頂点数Lの単純パスを見つける
bool color_coding(vector<vector<int>> &g, int L){
    int n = g.size();
    vector<int> a(n);
    vector<vector<bool>> dp(1 << L, vector<bool>(n));
    for(int i = 0; i < n; i++){
        a[i] = 1 << (xor64() % L);
    }
    for(auto &&u:g[0]) dp[a[u]][u] = true;
    for(int S = 1; S < (1 << L); S++){
        for(int v = 1; v < n; v++){
            if(!dp[S][v])continue;
            for(auto &&u:g[v]){
                if(!u || (S & a[u]))continue;
                dp[S | a[u]][u] = true;
            }
        }
    }
    for(auto &&u:g[0]) if(dp.back()[u])return true;
    return false;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    clock_t finish = clock() + CLOCKS_PER_SEC / 1000 * 960;
    int n, m, u, v;
    cin >> n >> m;
    vector<vector<int>> g(n);
    for(int i = 0; i < m; i++){
        cin >> u >> v;
        g[--u].push_back(--v);
        g[v].push_back(u);
    }
    while(clock() <= finish){
        if(color_coding(g, 4)){
            cout << "YES" << '\n';
            return 0;
        }
    }
    cout << "NO" << '\n';
}