You are given $*n*$ points on a plane. All points are different.

Find the number of different groups of three points $(*A*, *B*, *C*)$ such that point $*B*$ is the middle of segment $*AC*$.

The groups of three points are considered unordered, that is, if point $*B*$ is the middle of segment $*AC*$, then groups $(*A*, *B*, *C*)$ and $(*C*, *B*, *A*)$ are considered the same.

Input

The first line contains a single integer $*n*$ ($3 ≤ *n* ≤ 3000$) — the number of points.

Next $*n*$ lines contain the points. The $*i*$-th line contains coordinates of the $*i*$-th point: two space-separated integers $*x*_{*i*}, *y*_{*i*}$ ($- 1000 ≤ *x*_{*i*}, *y*_{*i*} ≤ 1000$).

It is guaranteed that all given points are different.

Output

Print the single number — the answer to the problem.