import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int sum = 0;

        while(true){

            //???????????¨??????????????????
            String x = br.readLine();
            //????????????????????????????´?
            char[] charKeta = x.toCharArray();

            //???????????¶
            if(x.equals("0")){
                break;
            }

            for(int i = 0; i < charKeta.length; i++){
                //char?????????int???????????£??????
                int intKeta = Character.getNumericValue(charKeta[i]);
                sum += intKeta;
            }
            System.out.println(sum);
            sum = 0;
        }
    }
}
/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