import java.util.*;

public class pre {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
		String str = s.next();
		int sum = 0;
		for(int i=0;i<str.length();i++){
			if(str.charAt(i) >= '0' && str.charAt(i) <= '9')
				sum += Integer.parseInt(String.valueOf(str.charAt(i)));
		}
		
		System.out.println(sum);
    }
}