import java.util.*;

public class Main {
    public static void main( String args[] ) {
        Scanner scan = new Scanner( System.in );
        
        while ( true ) {
            char[] charaArray = scan.nextLine().toCharArray();
            
            int result = 0;
            for( char chara: charaArray ) {
                result += Character.getNumericValue( chara );
                

            }
            if (result == 0) break;
            System.out.println(result);

        }
        scan.close();
        
    }
}
/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