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 di(int k)
{
	int re=0;
	while(k>0)
	{
		re+=k%10;
		k=k/10;
	}
	return re;
}
int main()
{
	int n,ans=1000000;
	scanf("%d",&n);
	for(int i=1;i<n;i++)
	{
		ans=min(ans,di(i)+di(n-i));
	}
	printf("%d",ans);
}
