#include <bits/stdc++.h>
using namespace std;
template <typename T>
void prinMatrix(string txt, vector<vector<T>> &a) {
  cout << txt;
  for (int i = 0; i < a.size(); ++i) {
    for (int j = 0; j < a[i].size(); ++j) cout << a[i][j] << ' ';
    cout << endl;
  }
}
template <typename T>
void printVector(string txt, vector<T> &a) {
  cout << txt;
  for (int i = 0; i < a.size(); ++i) cout << a[i] << ' ';
  cout << endl;
}
int n = 0;
vector<int> a;
int recur(int l, int sum) {
  if (l == 4) {
    if (sum == n / 2) return 1;
    return 0;
  }
  return recur(l + 1, sum + a[l]) | recur(l + 1, sum);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie();
  a.resize(4);
  for (int i = 0; i < 4; ++i) {
    cin >> a[i];
    n += a[i];
  }
  if (n % 2 == 1) {
    cout << "NO" << endl;
    return 0;
  }
  if (recur(0, 0))
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
