import java.util.Scanner;

public class Main {
    public static void main(String [] args){
        Scanner sc = new Scanner(System.in);
        
        while(true){
            String line = sc.nextLine();
            int sum = 0;
            
            if(line.charAt(0) == '0')break;
            
            for(int i = 0; i < line.length(); i++){
                sum += Character.digit(line.charAt(i), 10);
            }
            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