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) {
        try(Scanner sc = new Scanner(System.in)) {
            int N = sc.nextInt();
            int M = (int)Math.floor(N/2);
            int answer = Integer.MAX_VALUE;
            for ( int A = 1; A <= M; A++ ) {
                int B = N - A;
                int candidate = digitSum(A) + digitSum(B);
                if ( candidate < answer ) {
                    answer = candidate;
                }
            }
            System.out.println(answer);
        }
    }

    private static int digitSum(int n) {
        if ( n < 10 ) {
            return n;
        }
        else {
             int r = n % 10;
             int q = (n-r)/10;
             return r + digitSum(q);
        }
    }
}