import java.math.BigDecimal;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) throws NumberFormatException {
		Scanner scan = new Scanner(System.in);
		while(true){
			BigDecimal x = scan.nextBigDecimal();
			if(x.equals(BigDecimal.ZERO)){
				break;
			}
			int sum = 0;
			for(; !x.equals(BigDecimal.ZERO); x = x.divide(BigDecimal.TEN, 0, BigDecimal.ROUND_DOWN)){
				BigDecimal amari = x.divide(BigDecimal.TEN, 0, BigDecimal.ROUND_DOWN);
				amari = amari.multiply(BigDecimal.TEN);
				sum += x.subtract(amari).intValue();
			}
			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