#include <bits/stdc++.h>
using namespace std;
long long a[100005];
long long sum(long long a[], long long n) {
  long long s = 0;
  for (long long i = 0; i < n; i++) {
    s += a[i];
  }
  return s;
}
void input(long long a[], long long n) {
  for (int i = 0; i < n; i++) cin >> a[i];
}
int main(void) {
  input(a, 4);
  if (sum(a, 4) % 2 == 0) {
    sort(a, a + 4);
    if (a[0] + a[3] == a[1] + a[2])
      cout << "YES";
    else if (a[0] + a[1] + a[2] == a[3])
      cout << "YES";
    else
      cout << "NO";
  } else
    cout << "NO";
  return 0;
}
