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 <iostream>
using namespace std;
const int inf=1e9;
int n,ans=inf;
int nums(int x){int res=0;while(x){res+=x%10;x/=10;}return res;}
signed main()
{
	cin>>n;
	for (int i=1;i<=n/2;++i) ans=min(ans,nums(i)+nums(n-i));
	cout<<ans<<endl;
	return 0;
}