4A. Pouri is less than Parham

500 pts2s256 MB

You are given an integer $n$ .

You have exactly $n$ apples, and you want to distribute all of them between two people: Pouri and Parham.

Let $p$ be the number of apples given to Pouri and $q$ be the number of apples given to Parham. You must have:

Your goal is to maximize $p$ . Output this maximum possible value of $p$ .

Constraints

$n$

$\max p$

Input

Output

Input

Output

You are given an integer $n$ .

You have exactly $n$ apples, and you want to distribute all of them between two people: Pouri and Parham.

Let $p$ be the number of apples given to Pouri and $q$ be the number of apples given to Parham. You must have:

Your goal is to maximize $p$ . Output this maximum possible value of $p$ .

$\max p$