#include <bits/stdc++.h>
using namespace std;
int ans;
char a[10001];
int main() {
  scanf("%s", a + 1);
  int l = strlen(a + 1);
  for (int i = 1; i <= l; i++) {
    if ((a[i] >= 'A') && (a[i] <= 'Z')) ans += a[i] + 1 - 'A';
    if ((a[i] >= 'a') && (a[i] <= 'z')) ans -= a[i] + 1 - 'a';
  }
  printf("%d", ans);
  return ~~(0 - 0);
}
