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

int main() {
  int N, M, A;
  cin >> N >> M;
  map<int, int> MA;
  while (cin >> A) MA[A]++;
  for (auto [a, b] : MA) if (b % 2) return cout << "NO" << "\n", 0;
  cout << "YES" << "\n";
}