

import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		//????????£?????????????????????
		Scanner sc = new Scanner(System.in);
		//
		while(true){
		//??£?¨??????????????????????
		long sum = 0;
		//1??????????????????
		String line = sc.nextLine();
		//?????£?????\???????????????1???
		if(line.length()==1){
			//?????£?????\????????????1??????0?????£?????´????????????
			if(Integer.parseInt(line)==0){
				break;
				}
			}
			//
			for(int i=0;i<line.length();i++){
				sum += Integer.parseInt(String.valueOf(line.charAt(i)));
			}
			//
			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