#include <bits/stdc++.h>
using namespace std;
int main() {
  char a;
  int b;
  int c;
  int d;
  int e;
  cin >> a >> b >> c;
  if (a + b == c || a + c == b || b + c == a) {
    cout << "Yes"
         << "\n";
  } else {
    cout << "No"
         << "\n";
  }
  cin >> e;
}
