package yukicoder289;
import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		String str=sc.next();
		char[] s=str.toCharArray();
		int ret=0;
		for(char c:s){
			if(c>='0'&&c<='9'){
				ret+=c-'0';
			}
		}
		System.out.println(ret);
	}
}