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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>

int main(){
    int n,ans=0, i,b;
    int flag = 0;
    scanf("%d", &n);
    for(i=0;i<6;i++){
        b = n%10;
        if(b!=0){
            flag = 1;
        }
        n = n/10;
        ans += b;
    }
    if(flag == 0 ){
        ans = 10;
    }
    printf("%d\n", ans);
    return 0;
}