import java.io.*;

public class Main{
    public static void main(String[]args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
       
       while(true){
           String str =br.readLine();
           if(str.equals("0")){
               break;
           }
           int sum=0;
           for(int i=0;i<str.length();i++){
               sum+=Character.getNumericValue(str.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