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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;

class MainClass {
    static void Main() {
        int ans = 10000000;
        int n = int.Parse(Console.ReadLine());
        for (int i = 0; i < n / 2 + 5; i++) {
            int now = 0;
            now += n % 10;
            for (int j = 1; j < 7; j++) {
                now += (n / (10 * j))% 10;
            }
            ans = Math.Min(ans, now);
        }
        Console.WriteLine(ans);
    }
}