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) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int min = Integer.MAX_VALUE;
    for (int i = 1; i <= (N / 2); i++) {
      int a_sum = digitSum(i);
      int b_sum = digitSum(N - i);
      if (a_sum + b_sum < min) {
        min = a_sum + b_sum;
      }
    }
    System.out.println(min);
  }

  public static int digitSum(int num) {
    int tmp = num;
    int sum = 0;
    while (tmp > 0) {
      sum += (tmp % 10);
      tmp /= 10;
    }
    return sum;
  }
}