Problem:
Score : 200 points

Problem Statement

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".

Sample Input 1

15

Sample Output 1

6

When A=2 and B=13, the sums of their digits are 2 and 4, which minimizes the value in question.

Sample Input 2

100000

Sample Output 2

10

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {
  public static void main (String[] args) {
    Scanner input = new Scanner(System.in);
    
    while (input.hasNext()) {
      int N = input.nextInt();
      int halfN = N / 2;
      int minSum = Integer.MAX_VALUE;
      
      for (int i = 1; i < halfN; ++i) {
        minSum = Math.min(minSum, digitSum(i) + digitSum(N - i));
      }

      System.out.println(minSum);
    }
  }

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