#include <bits/stdc++.h>
using namespace std;
int ans;
string in;
int main(void) {
  cin >> in;
  for (int i = 0; i < in.length(); i++) {
    if (in[i] >= 'A' && in[i] <= 'Z')
      ans += in[i] - 'A' + 1;
    else if (in[i] >= 'a' && in[i] <= 'z')
      ans -= in[i] - 'a' + 1;
  }
  cout << ans << endl;
  return 0;
}
