import java.util.Scanner;                                                   

public class Main {
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        while(true){
            String a = in.nextLine();
            if(a.equals("0")){
                break;
            }
            int s = 0;
            String sary[] = a.split("");
            for (int i = 0; i < a.length(); i++){
                s += Integer.parseInt(sary[i]);
            }
            System.out.println(s);
        }
        }
}
/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