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Description

To facilitate Little Blue's learning, his mother prints out the materials provided by the teacher. For environmental protection, she usually prints on both sides of the paper, meaning both the front and back of each sheet are used. For example: if an electronic document has $3$ pages, it requires $2$ sheets of paper to print; if an electronic document has $4$ pages, it still requires $2$ sheets of paper to print. Given the number of pages $N$ in an electronic learning material, can you help Little Blue calculate how many sheets of paper are needed?

Input Format

An integer $N$ ($0≤N≤1000$), representing the number of pages in the electronic learning material.

Output Format

The number of sheets of paper needed for double-sided printing.

Sample

7

4