#include <bits/stdc++.h>
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;
typedef unsigned long long ull;


int main(){
  int N, M;
  cin >> N >> M;
  vector<int> v(N,0);
  rep(i,M){
    int a, b;
    cin >> a >> b;
    v[a]++;
    v[b]++;
  }

  int odd = 0;
  rep(i,v.size()){
    if(v[i]%2==1) odd++;
  }

  if(odd == 0 || odd == 2){
    cout << "YES" << endl;
  }else{
    cout << "NO" << endl;
  }
  
  return 0;
}