public class Main {
    public static void main(String[] args) {

        // ?????????????????\???????????????????????????????????????.
        java.util.Scanner sc = new java.util.Scanner(System.in);

        // ?????????????????????????????¨??????????´???????.
        // ???????????? char ???????????????????????????.
        // ???????????°??????????????????
        // ??????????????°??????????????¨???.
        while (true) {
            String s = sc.nextLine();
            char[] c = s.toCharArray();
            if (c[0] == '0') { break; }
            int sum = 0;
            for (int i = 0; i < s.length(); i ++) { sum += c[i] - '0'; }
            System.out.println(sum);
        }
    }
}
/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