package yukicoder;

import java.util.Scanner;

public class N289 {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String hoge = sc.nextLine();
		int meu = 0;
		char c;
		for(int i = 0;i < hoge.length();++i){
			c = hoge.charAt(i);
			if(c - 48 > 0 && c - 48 < 10){
				meu += c - 48;
			}
		}
		System.out.println(meu);
	}
}