Takahashi has two positive integers A and B.

It is known that A plus B equals N. Find the minimum possible value of "the sum of the digits of A" plus "the sum of the digits of B" (in base 10).

Constraints

* 2 ≤ N ≤ 10^5
* N is an integer.

Input

Input is given from Standard Input in the following format:


N


Output

Print the minimum possible value of "the sum of the digits of A" plus "the sum of the digits of B".

Examples

Input

15


Output

6


Input

100000


Output

10
import java.util.*;
public class Main {
	public static void main(String[] args){
		digitSum();
	}
	
	public static void digitSum() {
		Scanner sc = new Scanner(System.in);
		int num = sc.nextInt();
		int a = num/2, b = a;
		if (num % 2 != 0) a += 1;
		int res = Integer.MAX_VALUE;
		while (a < num && b > 0) {
			res = Math.min(res, digit(a) + digit(b));
			a++;
			b--;
		}
		System.out.println(res);
	}
	
	public static int digit(int a) {
		int res = 0;
		while (a > 0) {
			res += a % 10;
			a /= 10;
		}
		return res;
	}
}