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 void main (String[] args) {
		Scanner sc = new Scanner(System.in);
//------------------------------------------------------------
		int N =sc.nextInt();
		sc.close();
		int ans =1+digitSum(N-1);
		for (int A=1; A<N; A++) {
			int B =N-A;
			ans = Math.min(ans, digitSum(A)+digitSum(B));
		}
		System.out.println(ans);

//------------------------------------------------------------
	}
	public static int digitSum(int n) {
		int digitSum = 0;
		while(n>0) {
			digitSum +=n%10;
			n /= 10;
		}
		return digitSum;
	}
}