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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function main(input) {
  var digits = input.toString().length;
  var input = parseInt(input, 10);

  var divisor = Math.pow(10, digits - 1);
  var arr = [];
  for (var i = 0; i < digits; i++) {
  	arr.push(Math.floor(input / divisor))
  	input = input % divisor;
  	divisor /= 10;

  }
  var answer = arr.reduce((a, b) => a + b);
  if(answer = 1) answer = 10;

  console.log(answer);

}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));