#include <bits/stdc++.h>
using namespace std;
int a[5], dp[1000];
int sum = 0;
int main() {
  for (int i = 1; i <= 4; i++) {
    cin >> a[i];
    sum += a[i];
  }
  if (sum % 2 == 1) {
    cout << "NO";
    return 0;
  }
  for (int i = 1; i <= 4; i++) {
    for (int j = sum / 2; j >= a[i]; j--)
      dp[j] = max(dp[j], dp[j - a[i]] + a[i]);
  }
  if (dp[sum / 2] == sum / 2)
    cout << "YES";
  else
    cout << "NO";
  return 0;
}
