#include <bits/stdc++.h>   using namespace std;   signed main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     long long a, b, c, d;     cin >> a >> b >> c >> d;     long long sum = a + b + c + d;     if (sum % 2 == 0) {       if (a + b == sum / 2 || a + c == sum / 2 || a + d == sum / 2 ||           b + c == sum / 2 || b + d == sum / 2 || c + d == sum / 2 ||           a == sum / 2 || b == sum / 2 || c == sum / 2 || d == sum / 2)         cout <<  YES  << endl;       else         cout <<  NO  << endl;     } else       cout <<  NO  << endl;   }   