#include <bits/stdc++.h>
using namespace std;
int main() {
  long long sum = 0, sumt = 0;
  long long *A = new long long[4];
  for (long long i = 0; i < 4; i++) cin >> A[i];
  for (long long i = 0; i < 4; i++) {
    sum += A[i];
  }
  if (sum % 2 == 0) {
    sum /= 2;
  } else {
    cout << "NO";
    exit(0);
  }
  for (int i = 1; i < 4; ++i) {
    for (int r = 0; r < 4 - i; r++) {
      if (A[r] < A[r + 1]) {
        int temp = A[r];
        A[r] = A[r + 1];
        A[r + 1] = temp;
      }
    }
  }
  for (long long i = 0; i < 4; i++) {
    sumt += A[i];
    if (sumt == sum) {
      cout << "YES";
      exit(0);
    } else {
      if (sumt > sum) {
        sumt -= A[i];
      }
    }
  }
  cout << "NO";
  return 0;
}
