import java.util.*;
import java.text.*;
/*
Main class for AOJ where there is no input.
*/
public class Main{
   public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      String str;
      int sum;
      
      while(true){
         sum = 0;
         str = sc.nextLine();
         if(str.equals("0")){
            break;
         }else{
            for(int i = 0; i < str.length(); i ++){
               sum += Character.getNumericValue(str.charAt(i));
            }
            System.out.println(sum);
         }
         
         
      }
   }//main
}//class
/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