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<cstdio>
#include<iostream>
using namespace std;
int n,sum=1e9;
int ans(int x)
{
	int t=0;
	while (x)
	{
		t+=x%10;
		x/=10;
	}
	return t;
}
int main()
{
	scanf("%d",&n);
	for (int i=1;i<n;i++)
		sum=min(sum,ans(i)+ans(n-i));
		printf("%d",sum);
}