import java.util.Scanner;
import java.lang.Character;

class main{
    public static void main(String args[]){
	Scanner scan = new Scanner(System.in);
	
	int ans = 0;

	String str = scan.next();

	for(int i = 0; i < str.length(); i++){
	    char ch = str.charAt(i);
	   
	    if( Character.isDigit(ch) ){
		ans += Integer.parseInt("" +ch);
	    }
	}

	System.out.println(ans);

    }
}