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 (Clang 3.8.0) (judge verdict: Wrong Answer)

#include <stdio.h>

int main(){
    int e;
    int x;
    int er;
    int is;
    int es;
    int data;
    is=0;
    es=0;
    data=100000;
    scanf("%d",&e);
        for(int i=2;i<=e;i++){
            x=i;
            er=e-x;
            while(x>=10){
                is=is+x%10;
                x=x/10;
            }
            while(er>=10){
                es=es+er%10;
                er=er/10;
            }
            is=is+x;
            es=es+er;
            if(is+es<data){
                data=is+es;
            }
            is=0;
            es=0;
        }
    printf("%d\n",data);
    return 0;
}