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>

int main(){
		int n,ans=0;
		scanf("%d",&n);
		if(n<=10)ans=n;
		else if(n==100||n==1000||n==10000||n==100000)ans=10;
		else {
				while(n>0){
						int tmp=n%10;
						ans+=tmp;
						n=(n-tmp)/10;
				}
		}
		printf("%d\n",ans);
		return 0;
}