#include <bits/stdc++.h>
using namespace std;
int main() {
  vector<int> arr(4, 0);
  int sum = 0;
  for (int i = 0; i < 4; i++) {
    cin >> arr[i];
    sum += arr[i];
  }
  if (sum % 2 == 1) {
    cout << "NO" << endl;
    goto done;
  }
  sum /= 2;
  if (arr[3] == sum) {
    cout << "YES" << endl;
    goto done;
  }
  for (int i = 2; i >= 0; i--)
    if (arr[i] + arr[3] == sum) {
      cout << "YES" << endl;
      goto done;
    }
  for (int i = 2; i >= 0; i--) {
    for (int j = i - 1; j >= 0; j--)
      if (arr[i] + arr[j] + arr[3] == sum) {
        cout << "YES" << endl;
        goto done;
      }
  }
  cout << "NO" << endl;
done:
  return 0;
}
