#include <bits/stdc++.h>
const char* CS =
    ".0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
int main() {
  char s[64];
  scanf("%s", &s[1]);
  int n = strlen(&s[1]), ans = 0;
  for (int i = 1; i <= n; i++) {
    if ('A' <= s[i] && s[i] <= 'Z')
      ans += s[i] - 'A' + 1;
    else if ('a' <= s[i] && s[i] <= 'z')
      ans -= s[i] - 'a' + 1;
  }
  printf("%d\n", ans);
}
