#include <bits/stdc++.h>
using namespace std;
char c[100];
int main() {
  scanf("%s", c);
  int l = strlen(c), s = 0;
  for (int i = 0; i < l; i++)
    if (c[i] >= 'A' && c[i] <= 'Z')
      s += c[i] - 'A' + 1;
    else if (c[i] >= 'a' && c[i] <= 'z')
      s -= c[i] - 'a' + 1;
  printf("%d\n", s);
  return 0;
}
