Polygons

Time Limit: 1 sec

 

The Problem

There is a N sided polygon. How many triangles you can form from that N sided triangle ?

 

 

The Input

Input will be a number (2<N<1000) denoting the number of sides of the polygon.

 

The Output

The output will be the amount triangle that can be formed and should be printed in a separate line.

 

Sample Input

5

 

Sample Output

3

 

 

 

 

 

Problem Setter: Parag Paul