#include <iostream>
#include <string>

using namespace std;

int main() {
  int sum;
  string s;
  cin >> s;
  
  for (auto &c:s) {
    if (c!='0') {
      sum+=c-'0';
    } else {
      sum+=10;
    }
  }

  cout << sum << endl;
  return 0;
}