import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner scan=new Scanner(System.in);
		String x;
		int ans;
		while(true){
			x=scan.next();
			ans=0;
			if(x.equals("0")) break;
			for(int i=0;i<x.length();i++){
				ans=ans+x.charAt(i)-'0';
			}
			System.out.println(ans);
		}
		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