import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		for(int b = 1;b>0;b++){
			String r = scan.next();
			int tot = 0;
			if(r.equals("0")){
				break;
			}
			for(int a = 1; a<=r.length();a++){
				String k = r.substring(a-1,a);
				int K = Integer.parseInt(k);
				tot = tot + K;
			}
			System.out.println(tot);
		}
	}
}
/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