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