import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String string = scan.nextLine();
        char[] a = string.toCharArray();

        while (a[0] != '0') {
            int i = 0;
            int sum = 0;
            while (i < a.length) {
                sum += a[i++] - '0';
            }
            System.out.println(sum);
            string = scan.nextLine();
            a = string.toCharArray();
        }
    }
}
/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