Dividing Circles
By Francisco Elio Parente Arcos Filho, UEA 
Brazil
By Francisco Elio Parente Arcos Filho, UEA Brazil
Given a set of N points on a circumference of a circle, every pair of points is connected by a segment and three of those segments never cross each other in a point inside the circumference.
Your task is to determine in how many parts these segments divide the interior of the circle.
The first and only line of the input contains an integer N (1 ≤ N ≤ 1000) representing the number of points on the circumference.
The output consists of a single line containing an integer representing the number of parts of the circle.
| Input Samples | Output Samples |
|
1 |
1 |
|
2 |
2 |
|
3 |
4 |
|
4 |
8 |
|
5 |
16 |