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,i,j,x,ans=1e9;
int main () {
	for(scanf("%d",&n),i=1;i<n;++i){
		for(x=0,j=i;j;j/=10)x+=j%10;
		for(j=n-i;j;j/=10)x+=j%10;
		ans=min(ans,x);
	}
	printf("%d\n",ans);
}