import java.util.*; 

public class test {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		String str = sc.next();
		String a = str.replaceAll("[^0-9]","");
		int sum = 0;
		
		for(int i=0; i<a.length(); i++ ){
			sum = sum + Integer.parseInt("" + a.charAt(i));
		}
		System.out.println(sum);
	}
}