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 n,Ans;
inline int dig(int X)
{
	int sum=0;
	while(X) sum+=X%10,X/=10;
	return sum;
}
int main()
{
	Ans=0x3fffffff;
	cin >> n;
	for(int i=1;i<n;i++)
		Ans=min(Ans,dig(i)+dig(n-i));
	cout << Ans << endl;
}