import java.io.*;
public class Main {
    public static void main(String[] args) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        while (true) {
            int i,sum=0;
            try {
                String line = reader.readLine();
                if(line.equals("0")) break;
                for(i=0;i<line.length();i++) {
                    char c = line.charAt(i);
                    sum += Character.getNumericValue(c);
                }
            } catch (IOException e) {
                System.out.println(e);
            }
            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