import java.util.Scanner;
import java.util.Arrays;

class Main{
	public static void main(String[] args){
		Scanner scanner = new Scanner(System.in);
		
		while(true){
			String s = scanner.next();
			int sum = 0;

			for(int i = 0; i < s.length(); i++){
				char ch = s.charAt(i);
				sum += Character.getNumericValue(ch);
			}
			
			if(sum == 0){
			    break;
			}

			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