import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(true){
            String x=sc.next();
            if(x.equals("0"))break;
            int sum=0;
            for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            }
            System.out.println(sum);
        }
    }
}

 import java.util.Scanner; Scanner java.util public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(true){
            String x=sc.next();
            if(x.equals("0"))break;
            int sum=0;
            for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            }
            System.out.println(sum);
        }
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(true){
            String x=sc.next();
            if(x.equals("0"))break;
            int sum=0;
            for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            }
            System.out.println(sum);
        }
    } main {
        Scanner sc = new Scanner(System.in);
        while(true){
            String x=sc.next();
            if(x.equals("0"))break;
            int sum=0;
            for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            }
            System.out.println(sum);
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) while(true){
            String x=sc.next();
            if(x.equals("0"))break;
            int sum=0;
            for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            }
            System.out.println(sum);
        } true {
            String x=sc.next();
            if(x.equals("0"))break;
            int sum=0;
            for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            }
            System.out.println(sum);
        } String x=sc.next(); x sc.next() sc.next sc if(x.equals("0"))break; x.equals("0") x.equals x "0" break; int sum=0; sum 0 for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            } int i=0; int i=0; i 0 i<x.length() i x.length() x.length x i++ i++ i {
                sum+=(x.charAt(i)-'0')%10;
            } {
                sum+=(x.charAt(i)-'0')%10;
            } sum+=(x.charAt(i)-'0')%10 sum (x.charAt(i)-'0')%10 (x.charAt(i)-'0') x.charAt(i) x.charAt x i '0' 10 System.out.println(sum) System.out.println System.out System System.out sum String[] args args public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(true){
            String x=sc.next();
            if(x.equals("0"))break;
            int sum=0;
            for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            }
            System.out.println(sum);
        }
    }
} public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(true){
            String x=sc.next();
            if(x.equals("0"))break;
            int sum=0;
            for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            }
            System.out.println(sum);
        }
    }
} Main
import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(true){
            String x=sc.next();
            if(x.equals("0"))break;
            int sum=0;
            for(int i=0;i<x.length();i++){
                sum+=(x.charAt(i)-'0')%10;
            }
            System.out.println(sum);
        }
    }
}


