Description

In the computer science class, students are grouped for the final report based on their seat numbers, with 3 students per group. For example, students 1, 2, and 3 form the first group; students 4, 5, and 6 form the second group, and so on. Given a student's seat number, determine which group they belong to.

Input Format

A single line containing a positive integer $n$ ($1 \leq n \leq 60$), representing the student's seat number.

Output Format

Output the group number.

Sample

7

3