import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);

        long sum;
        String input;
        while (true){
            sum = 0;
            input = scanner.nextLine();

            if(input.equals("0")){
                break;
            }

            String[] mash = input.split("");

            for(String txt : mash){
                sum += Integer.parseInt(txt);
            }
            System.out.println(sum);
        }
        scanner.close();
    }
}


/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