#!/usr/bin/env perl

use strict;
use utf8;
use warnings;

if ($0 eq __FILE__) {
  my $line = <STDIN>;
  my $val = 0;
  foreach my $ch (split //, $line) {
    if ($ch eq "\n") {
      last;
    }
    if ($ch eq "0") {
      $val += 10;
    } else {
      $val += $ch;
    }
  }
  printf("%d\n", $val);
}