Area of Arrow

Time Limit: 1 sec

 

The Problem

An arrow is formed in an N x N square by joining the bottom corners to the midpoint of the top edge and the center of the square.

 

 

You have to find the area of the arrow.

 

The Input

Input file contain several lines of input. Each line of input consists an integer N (1<N<=100).

 

The Output

For each line of input print a line of output – area of the arrow. The area is to be printed accurately rounded to three decimals.

 

Sample Input

2

6

 

Sample Output

1.000

9.000

 

 

 

Inter University Programming Contest - 2015 [BGC Trust University Bangladesh]

Problem Setter: Md. Helal Uddin