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 Scala (2.11.7) (judge verdict: Runtime Error)

import java.io.{InputStream, OutputStream, PrintStream}
import java.util.Scanner

object Main {

  def main(args: Array[String]): Unit = {
    val solver = new Solver(System.in, System.out)
    solver.solve()
  }

  class Solver(in: InputStream, out: OutputStream) {
    lazy val input = new Scanner(in)

    lazy val output = new PrintStream(out)

    def solve(): Unit = {
      val n = input.nextLine().toInt

      output.println {
        1.until(n).map { i =>
          val a = i
          val b = n - i
          (a.toString.split("") ++ b.toString.split("")).map(_.toInt).sum
        }.min
      }
    }

  }

}