#include <iostream>
#include <algorithm>
using namespace std;
 
int main() {
  int a[3];
  for (int i = 0; i < 3; ++i) cin >> a[i];
  sort(a[3].begin(), a[3].end());
  if (a[0]+a[1] == a[2]) { cout << "YES"; }
  else { cout << "NO"; }
  return 0;
}