### COCI 2007/2008, Contest #2

## Task PRAVOKUTNI

N points are placed in the coordinate plane.

Write a program which calculates in how many ways a **right triangle** can be
formed by three of the given points. A right triangle is one in which one of the
angles is 90 degrees.

### Input

The first line of input contains an integer `N` (3 ≤ N ≤ 1500), the number of points.

Each of the following N lines contains the coordinates of one
point, two integers separated by a space. The coordinates will be between -10^{9} and 10^{9}.

No two points will be located at the same coordinates.

### Output

Output the number of right triangles.

### Examples

## Input3 4 2 2 1 1 3 ## Output1 |
## Input4 5 0 2 6 8 6 5 7 ## Output0 |
## Input5 -1 1 -1 0 0 0 1 0 1 1 ## Output7 |

All Submissions

Best Solutions

**Point Value:** 20 (partial)

**Time Limit:** 4.00s

**Memory Limit:** 32M

**Added:** Nov 13, 2010

**Languages Allowed:**

C++03, PAS, C, HASK, ASM, RUBY, PYTH2, JAVA, PHP, SCM, CAML, PERL, C#, C++11, PYTH3

## Comments (Search)

ilovepion Jan 06, 2011 - 2:06:25 am UTC Lol fail typobbi5291on Jan 06, 2011 - 3:03:04 pm UTC Re: Lol fail typo