import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String input = sc.next();
		sc.close();
		String regex = "[^0-9]";
		Pattern p = Pattern.compile(regex);

		Matcher m = p.matcher(input);
		String inputA = m.replaceAll("");
		char[] charStr = inputA.toCharArray();
		int result = 0;
		for(char charNum : charStr){
			result += Character.getNumericValue(charNum);
		}
		System.out.println(result);

	}// mainmethod

} // class