import java.io.*;
import java.util.*;

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

        InputStreamReader isr =new InputStreamReader(System.in);
   		BufferedReader br =new BufferedReader(isr);
    	String buf = br.readLine();
        
        while (true) {
            int i, sum = 0;
            if (Character.getNumericValue(buf.charAt(0)) == 0) break;
            for (i = 0;i < buf.length();i++) {
                sum += Character.getNumericValue(buf.charAt(i));
            }
            System.out.println(sum);
            buf = br.readLine();
        }
    }
}
/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