import java.util.Scanner;

/**
 * @author SS-1029
 *
 */
public class Main {

	public static void main(String[] args) {

		//??\??????????????????????????????Scanner???????????§???????????????
		Scanner scan = new Scanner(System.in);


		while(true){
			//??????????????????
			String x = scan.nextLine();
			//???????????¶
			if(x.charAt(0) == '0'){
				break;
			}
			//???????????¨???
			System.out.println(getSum(x));
		}
	}

	/*
	 * ?¨??????????????????????
	 * @param String x
	 * @param return int sum
	 */
	public static int getSum(String x) {

		//??????????????£?¨?
		int sum = 0;
		//char?????????????????°?????????
		for(int i = 0; i < x.length(); i++){
			//String?????????????????°?????????
			sum += Integer.parseInt(String.valueOf(x.charAt(i)));
		}
		return 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