import java.util.Scanner;
import java.lang.Math;
import java.lang.StringBuilder;
import java.util.regex.Pattern;

    public class Main {
        public static void main(String[] args) {
            Scanner sc = new Scanner(System.in);
            
            String s = sc.nextLine();
            StringBuilder sb = new StringBuilder(s);
            
            int ans = 0;
            for(int i=0; i<s.length(); i++){
                if(sb.charAt(i)<'9'){
                    ans += Character.getNumericValue(sb.charAt(i));
                }else{
                    continue;
                }
            }
            System.out.println(ans);
        }
    }