

import java.util.Scanner;

public class Main{

	public static void main(String[] args) {

		int sum = 0;
		StringBuilder out = new StringBuilder();
		
		// 標準入力
		Scanner sc = new Scanner(System.in);
		
		while (sc.hasNext()) {
			String words = sc.next();
			
			if(words.equals("0"))
			break;
			
			char ch[] = words.toCharArray();

			//
			sum = 0;
			for (int i = 0; i < ch.length; i++) {
				//
				String str = String.valueOf(ch[i]);
				int num = Integer.parseInt(str);
				sum += num;
			}
			out = new StringBuilder(out+(sum+"\n"));
		}

		// 結果出力
		System.out.print(out);

	}

}
/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