import java.util.Scanner;

class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);
        while (true) {
            String number = scan.nextLine();
            int num = 0;
            if (number.equals("0")) {
                break;
            }
            for(int i = 0; i < number.length(); i++) {
                char ch = number.charAt(i);
                num += Character.getNumericValue(ch);
            }
                System.out.println(num);
        }
    }
}
/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