#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <iostream>
#include <queue>
#include <list>
#include <stack>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;

int depth[20005];
vector<int> v[20005];
int A[50005],B[50005];
map<int,map<int,int> > memo;

int main(){
  ios::sync_with_stdio(false);
  int N, M;
  cin >> N >> M;
  rep(i,M){
    int a, b;
    cin >> a >> b;
    v[a].push_back(b);
    v[b].push_back(a);
    A[i] = a;
    B[i] = b;
  }

  rep(i,v[1].size()){
    int a = v[1][i];
    rep(j,v[a].size()){
      int b = v[a][j];
      if(b == 1) continue;
      memo[b][a] = 1;
    }
  }

  bool ret = false;
  rep(i,M){
    int szA = memo[A[i]].size();
    if(memo[A[i]].count(B[i])>0) szA--;
    int szB = memo[B[i]].size();
    if(memo[B[i]].count(A[i])>0) szB--;

    if(szA == szB && szA == 1){
      map<int,int> cnt;
      FOR(it,memo[A[i]]){
        cnt[it->first]++;
      }
      FOR(it,memo[B[i]]){
        cnt[it->first]++;
      }
      FOR(it,cnt){
        if(it->second == 1) ret = true;
      }
    }
    else if(szA>0 && szB>0 && 2<=max(szA, szB)){
      ret = true;
    }
  }

  
  if(ret) cout << "YES" << endl;
  else cout << "NO" << endl;
  
  return 0;
}