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: Accepted)

#include<stdio.h>
digit(int a)
{
    int rem,div,sum=0;
    while(1)
    {rem=a%10;
    div=a/10;
    sum=sum+rem;
    a=div;
    if(a==0)break;
    }
    return sum;

}
main()
{
    int n,i=1,sum=0,min=1000000,a,b;
    scanf("%d",&n);
    while(i<n)
    {a=i;
    b=n-i;

    sum=digit(a)+digit(b);
    if(sum<min)min=sum;
    i++;


    }
    printf("%d\n",min);
    return 0;
}