#include <bits/stdc++.h>
using namespace std;
void Sieve(long long n) {
  bool prime[n + 1];
  memset(prime, true, sizeof(prime));
  for (long long p = 2; p * p <= n; p++)
    if (prime[p] == true)
      for (long long i = p * p; i <= n; i += p) prime[i] = false;
}
long long MIN(long long x, long long y) { return x > y ? y : x; }
long long MAX(long long x, long long y) { return x > y ? x : y; }
void swap(long long *x, long long *y) {
  long long temp = *x;
  *x = *y;
  *y = temp;
}
bool isPrime(long long n) {
  if (n <= 1) return false;
  if (n <= 3) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  long long p = sqrt(n);
  for (long long i = 5; i <= p; i = i + 6)
    if (n % i == 0 || n % (i + 2) == 0) return false;
  return true;
}
long long gcdExtended(long long a, long long b, long long *x, long long *y) {
  if (a == 0) {
    *x = 0, *y = 1;
    return b;
  }
  long long x1, y1;
  long long gcd = gcdExtended(b % a, a, &x1, &y1);
  *x = y1 - (b / a) * x1;
  *y = x1;
  return gcd;
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
const long long MOD = 1e9 + 7, N = 2e5 + 5, bit = 64, Big = 1e18;
long long mod_pow(long long a, long long b, long long M = MOD) {
  long long res = 1;
  while (b) {
    if (b & 1) res = (res * a) % M;
    a = (a * a) % M;
    b >>= 1;
  }
  return res;
}
void start() {
  long long arr[4], sum = 0;
  for (long long i = 0; i < 4; i++) {
    cin >> arr[i];
    sum += arr[i];
  }
  sort(arr, arr + 4);
  if (!(sum & 1)) {
    if ((arr[0] + arr[3] == arr[1] + arr[2]) ||
        (arr[0] + arr[1] + arr[2] == arr[3]))
      cout << "YES";
    else
      cout << "NO";
  } else
    cout << "NO";
}
signed main() {
  long long test = 1;
  while (test--) start();
}
