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".

Examples

Input

15


Output

6


Input

100000


Output

10
#include <stdio.h>
int main(){
	int i,n,a,b,s,mn=1e9;
	scanf("%d",&n);
	for(i=1;i<n;++i){
		s=0;
		for(a=i;a;a/=10)s+=a%10;
		for(b=n-i;b;b/=10)s+=b%10;
		if(mn>s)mn=s;
	}
	printf("%d",mn);
	return 0;
}
