import java.util.*;

public class Main {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        String checkStr=sc.next();
        String[] letters=checkStr.split("");
        int count=0;
        for(String letter:letters){
            if(!(letter.matches("[a-zA-Z]"))){
                count+=Integer.parseInt(letter);
            }
        }
        System.out.println(count);
    }
}