#include <bits/stdc++.h>
using namespace std;

int main() {
  string s;
  int a = 0;

  cin >> s;
  for (int i = 0; i < (int)s.size(); i++) {
    if (s[i] < 65) {
      a += s[i] - 48;
    }
  }
  cout << a << endl;
}