#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  getline(cin, s);
  long long ans = 0;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] >= 65 && s[i] <= 90) {
      ans += s[i] - 64;
    } else if (s[i] >= 97 && s[i] <= 122) {
      ans -= s[i] - 96;
    }
  }
  cout << ans << endl;
}
