import java.util.Scanner;

class Main {

	public static void main(String[] args) {

		char[] x;

		Scanner stdIn = new Scanner(System.in);

		boolean flag = true;
		while (flag) {
			int sum = 0;
			x = stdIn.nextLine().toCharArray();
			if(x[0] == '0') {
				break;
			}

			for (int j = 0; j < x.length; j++) {
				sum += Character.getNumericValue(x[j]);
			}
			System.out.println(sum);
		}
		stdIn.close();
	}
}
/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