#include <bits/stdc++.h>
using namespace std;
const int maxn = 55;
char ch[maxn];
int n, m, ans;
int main() {
  cin >> ch;
  n = strlen(ch);
  for (int i = 0; i < n; i++)
    if ('A' <= ch[i] && ch[i] <= 'Z')
      ans += (ch[i] - 'A' + 1);
    else if ('a' <= ch[i] && ch[i] <= 'z')
      ans -= (ch[i] - 'a' + 1);
  cout << ans;
  return 0;
}
