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<bits/stdc++.h>
using namespace std;
int calc(int x){
	int ans=0;
	while(x){
		ans+=x%10;
		x/=10;
	}
	return ans;
}
int main(){
	int n;
	scanf("%d",&n);
	int res=n;
	for (int i=1;i<n;i++){
		res=min(res,calc(i)+calc(n-i));
	}
	printf("%d\n",res);
}