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: Accepted)

object Main {
  def main(args: Array[String]) {
    val sum = io.StdIn.readLine.toInt
    val candidates = for (j <- (1 until sum)) yield (j, sum - j)
    println(candidates.map(t => sumOfEachRank(t._1) + sumOfEachRank(t._2)).min)
  }

  def sumOfEachRank(n: Int): Int =
    n.toString.map(_.asDigit).sum
}