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 Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.util.*;

class Reader {
  Scanner sc = new Scanner(System.in);

  public int ini() {
    return sc.nextInt();
  }

  public int[] vi(int n) {
    int[] a = new int[n];
    for (int i = 0; i < n; i++) a[i] = sc.nextInt();
    return a;
  }
}

public class Main extends Reader {
  public static void main(String[] args) {
    Main main = new Main();
    main.show(main.solve());
  }

  int n;

  public Main() {
    n = ini();
  }
  
  int solve() {
    int ans = 9999;
    for (int i = 1; i < n - 1; i++) {
      int j = n - i;
      int cnt = digitsum(i) + digitsum(j);
      if (cnt < ans) ans = cnt;
    }
    return ans;
  }

  int digitsum(int n) {
    int ans = 0;
    while (n > 0) {
      ans += n % 10;
      n /= 10;
    }
    return ans;
  }

  void show(int ans) {
    System.out.println(ans);
  }
}