Farmer John's largest pasture can be regarded as a large 2D grid of square "cells" (picture a huge chess board). Currently, there are NN cows occupying some of these cells (1≤N≤2001≤N≤200).Farmer John wants to build a fence that will enclose a square region of cells; the square must be oriented so its sides are parallel with the xx and yy axes, and it could be as small as a single cell. Please help him count the number of distinct subsets of cows that he can enclose in such a region. Note that the empty subset should be counted as one of these.

INPUT FORMAT (input arrives from the terminal / stdin):

The first line contains a single integer NN. Each of the next NN lines Each of the next NN lines contains two space-separated integers, indicating the (x,y)(x,y) coordinates of a cow's cell. All xx coordinates are distinct from each-other, and all yy coordinates are distinct from each-other. All xx and yy values lie in the range 0…1090…109.

Note that although the coordinates of cells with cows are nonnegative, the square fenced area might possibly extend into cells with negative coordinates.

OUTPUT FORMAT (print output to the terminal / stdout):

The number of subsets of cows that FJ can fence off. It can be shown that this quantity fits within a signed 32-bit integer.

SAMPLE INPUT:

4
0 2
2 3
3 1
1 0

SAMPLE OUTPUT:

14

In this example, there are 2424 subsets in total. FJ cannot create a fence enclosing only cows 1 and 3, or only cows 2 and 4, so the answer is 24−2**=16−2=**1424−2=16−2=14.

SAMPLE INPUT:

16
17 4
16 13
0 15
1 19
7 11
3 17
6 16
18 9
15 6
11 7
10 8
2 1
12 0
5 18
14 5
13 2

SAMPLE OUTPUT:

420

SCORING:

• In test cases 1-5, all coordinates of cells containing cows are less than 2020.
• In test cases 6-10, N≤20N≤20.
• In test cases 11-20, there are no additional constraints.