#include <bits/stdc++.h>   using namespace std;   int main() {     int arr[4];     cin >> arr[0] >> arr[1] >> arr[2] >> arr[3];     sort(arr, arr + 4);     if ((arr[0] + arr[3]) == (arr[1] + arr[2]) ||         (arr[0] + arr[1] + arr[2]) == arr[3]) {       cout <<  YES  <<   n ;     } else {       cout <<  NO  <<   n ;     }     return 0;   }   