import java.util.*;
public class Main {
    static Scanner kbd = new Scanner(System.in);
    public static void main(String[] args) {
 
    while(kbd.hasNext()){
        String n = kbd.next();
        if(!(n.equals("0"))){
        int sum = 0;
        int i=0;
        for(; i<n.length(); i++){
            String a = n.substring(i,i+1);
            //System.out.println(a);
            int b = Integer.parseInt(a);
            //System.out.println(sum+"+"+b);
            sum += b;
        }
            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