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>
int n,ans=100005;
int main()
{
	scanf("%d",&n);
	for(int i=1;i*2<=n;i++)
	{
		int a=i,b=n-i,cnt=0;
		while(a)
		{
			cnt+=a%10;
			a/=10;
		}
		while(b)
		{
			cnt+=b%10;
			b/=10;
		}
		if(cnt<ans) ans=cnt;
	}
	printf("%d\n",ans);
}