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 12.16.1) (judge verdict: Accepted)

function main(input) {
  let N = parseInt(input, 10);
  let ans;
  
  if (N === 10 || N === 100 || N === 1000 || N === 10000 || N === 100000) {
  	console.log(10);
    return;
  }
  
  while(true) {
    if (!ans) { 
      ans = Math.floor(N % 10);
    } else {
      ans += Math.floor(N % 10);
    };
    
    N = N / 10;
    
    if (N <= 0) { break; }
  }
  
  console.log(ans);
}

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