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 Kotlin (1.0.0) (judge verdict: Accepted)

fun main(args: Array<String>) {
    val n = readLine()!!.toInt()

    val answer = (2..(n / 2 + 1)).map {
        val a = it
        val b = n - a

        val sumA = a.toString()
                .map { Integer.parseInt(it.toString()) }
                .sum()
        val sumB = b.toString()
                .map { Integer.parseInt(it.toString()) }
                .sum()

//        println("a=$a, b=$b, sumA=$sumA, sumB=$sumB")

        Triple(a, b, sumA + sumB)
    }.minBy { it.third }

    println(answer?.third)
}