import java.util.Scanner;
class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		char[] Array = sc.next().toCharArray();
		int total = 0;
		for(char ch:Array) {
			if(ch == '1' || ch == '2' || ch == '3' || ch == '4' || ch == '5' || ch == '6' || ch == '7' || ch == '8' || ch == '9') {
				total += Character.getNumericValue(ch);
			}
		}
		System.out.println(total);
	}
}