import static java.lang.System.out;
import java.util.Scanner;

class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String num = scan.next();
        String[] numbers = num.split("");
        int ans = 0;
        while (!numbers[0].equals("0")) {
            for (String n : numbers) {
                ans += Integer.parseInt(n);
            }
            out.println(ans);
            num = scan.next();
            numbers = num.split("");
            ans = 0;
        }
    }   
}      
/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