import java.util.*;

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

   
}}}



/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz