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>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define TIME 3


int kurai(int n){
    int a=n;
int dig;
int sum=0;

while(a){
dig=a%10;
sum=sum+dig;
a=a/10;

}

return sum;
}



int main(void){
int a,b;
int n;
scanf("%d",&n);

a=n-1;
b=1;

int min=99999999;
int sum;
for(;;){
sum=kurai(a)+kurai(b);
if(min>=sum){min=sum;}
a--;
b++;
if(a==0||b==n){printf("%d\n",min);break;}
}


}