Problem Statement

We have $N$ distinct points on a two-dimensional plane, numbered $1,2,\\ldots,N$. Point $i$ $(1 \\leq i \\leq N)$ has the coordinates $(x_i,y_i)$.

How many rectangles are there whose vertices are among the given points and whose edges are parallel to the $x$- or $y$-axis?

Constraints

• $4 \\leq N \\leq 2000$
• $0 \\leq x_i, y_i \\leq 10^9$
• $(x_i,y_i) \\neq (x_j,y_j)$ $(i \\neq j)$
• All values in input are integers.

Input

Input is given from Standard Input in the following format:

$N$ $x_1$ $y_1$ $x_2$ $y_2$ $\\vdots$ $x_N$ $y_N$

Output

Print the answer.

Sample Input 1

6
0 0
0 1
1 0
1 1
2 0
2 1

Sample Output 1

3

There are three such rectangles:

the rectangle whose vertices are Points $1$, $2$, $3$, $4$,

the rectangle whose vertices are Points $1$, $2$, $5$, $6$,

and the rectangle whose vertices are Points $3$, $4$, $5$, $6$.

Sample Input 2

4
0 1
1 2
2 3
3 4

Sample Output 2

0

Sample Input 3

7
0 1
1 0
2 0
2 1
2 2
3 0
3 2

Sample Output 3

1