#include <bits/stdc++.h>
using namespace std;
int main() {
  int first = (cin >> (first), first), second = (cin >> (second), second),
      third = (cin >> (third), third);
  if ((first + second == third) || (second + third == first) ||
      (first + third == second))
    cout << "yes";
  else
    cout << "no";
  return 0;
}
