import java.util.Scanner;

public class Main {

    public static void main(String[] args)throws Exception {

        Scanner sc = new Scanner(System.in);

        while (!sc.hasNext("0")) {
            int sum = 0;
            String line = sc.nextLine();
            char[] ch = line.toCharArray();
            for (int i = 0; i < ch.length; i++) {
                sum += Integer.parseInt("" + ch[i]); 
            }
            System.out.println(sum);
            
        }
        sc.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