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: Accepted)

function Main(input) {
  var n = parseInt(input.split("\n")[0], 10);
  if (n === 10 || n === 100 || n === 1000 || n === 10000 || n === 100000) {
    console.log(10);
    return;
  } else {
    var sum = 0;
    while(n > 0) {
      sum += n % 10;
      n = Math.floor(n / 10);
    }
    console.log(sum);
    return;
  }
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));