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.Scanner;
public class Main {
	public static int sum(int a) {
		int ans = 0;
		while(a >= 10) {
			ans += a%10;
			a /= 10;
		}
		ans += a;
		return ans;
	}

	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		int N = stdIn.nextInt();
		int n = 0;
		if(N%2 == 0) {
			n = N/2;
		}
		else {
			n = (N+1)/2;
		}
		int ans = sum(1)+sum(N-1);
		
		for(int A = 1; A <= n; A++) {
			if(sum(A)+sum(N-A) < ans) {
				ans = sum(A)+sum(N-A);
			}
		}
		System.out.println(ans);

	}

}