import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        int sum=0,i=0,j;
        String t;
        Scanner s = new Scanner(System.in);
        while(true){
            t = s.next();
            if(t.charAt(0) =='0'&&t.length()==1)break;
            for(i=0;i<t.length();i++){
                sum+=t.charAt(i)-'0';
            }
            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