import java.io.*;
import java.util.*;
import java.lang.*;

class Main{
  public static void main(String[] args) throws java.lang.NumberFormatException{
    Scanner scan=new Scanner(System.in);

    while(true){
      String num=scan.next();
      if(num.equals("0"))break;

      long sum=0;

      for(int i=0;i<num.length();i++){
        sum+=Character.getNumericValue(num.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