#include <bits/stdc++.h>

using namespace std;

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)

using ll = long long;
using P = std::tuple<int,int>;

const int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1}, dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};

int N, M;
set<int> ones[20000];
bool one[20000];
vector<P> es;

int main(){
    //*
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);
    /*/
      /*/

    std::cin >> N >> M;

    for(int i=0;i<M;++i){
        int A, B;
        std::cin >> A >> B;

        --A; --B;

        if(A > B){swap(A, B);}
        if(A == 0){one[B] = true;}
        
        es.emplace_back(A, B);
    }

    for(const P& e : es){
        int u, v;
        tie(u, v) = e;

        if(u == 0){continue;}
        
        if(one[u]){ones[v].emplace(u);}
        if(one[v]){ones[u].emplace(v);}
    }
    
    bool isOk = false;
    for(const P& e : es){
        int u, v;
        tie(u, v) = e;

        int u_ones_n = ones[u].size() - (ones[u].find(v) != ones[u].end()),
            v_ones_n = ones[v].size() - (ones[v].find(u) != ones[v].end());

        if(u_ones_n < 1 || v_ones_n < 1){continue;}
        if(u_ones_n > 1 || v_ones_n > 1){isOk = true;}
        else{
            int x = (*ones[u].begin() != v) ? (*ones[u].begin()) : (*ones[u].rbegin()),
                y = (*ones[v].begin() != u) ? (*ones[v].begin()) : (*ones[v].rbegin());

            if(x != y){isOk = true;}
        }
    }

    if(isOk){
        std::cout << "YES" << std::endl;
    }else{
        std::cout << "NO" << std::endl;
    }
}