#include <bits/stdc++.h>
using namespace std;
const int N = 10;
int a[N][N];
void solve() {
  string t;
  cin >> t;
  int ans = 0;
  for (int i = 0; i < t.length(); ++i) {
    if (!isalpha(t[i])) continue;
    if (t[i] >= 'a' && t[i] <= 'z')
      ans -= t[i] - 'a' + 1;
    else
      ans += t[i] - 'A' + 1;
  }
  cout << ans << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  solve();
  return 0;
}
