#include <bits/stdc++.h>
using namespace std;
int main() {
  char m[51];
  scanf("%s", m);
  int res = 0, x, y, z;
  for (int i = 0; m[i] != '\0'; i++) {
    if ('@' < m[i] && m[i] < '[') {
      x = 1;
    } else
      x = 0;
    if ('`' < m[i] && m[i] < '{')
      y = 1;
    else
      y = 0;
    if (m[i] < 'a')
      z = m[i] - 'A' + 1;
    else
      z = m[i] - 'a' + 1;
    z = (x - y) * z + res;
    res = z;
  }
  printf("%d\n", res);
  return 0;
}
