VIII Olimpiada Informatyczna 2000/2001

Task: KOP
Author: Tomasz Waleń

III stage contest, the second day  

Byteman, one of the most deserving employee of The Goldmine of Byteland, is about to retire by the end of the year. The Goldmine management would like to reward him in acknowledgment of his conscientious work. As a reward Byteman may receive a small lot - a rectangular piece of the mine's area with sides of length s and w parallel to the axes of the coordinate system. He may choose the location of the lot. Of course, a value of the lot depends on the location. The value of the lot is a number of gold nuggets in the area of the lot (if a nugget lies on the border of the lot, then it is in the area of the lot). Your task is to write a program which computes the maximal possible value of the lot (the value of the lot with the best location). In order to simplify we assume that the terrain of the Goldmine is boundless, but the area of gold nuggets occurrence is limited.


Write a program which:


In the first line of the text file KOP.IN there are two positive integers s and w separated by a single space, (1<=s,w<=10 000); they denote the lengths of lot's sides - parallel to the OX-axe and OY-axe respectively. There is one positive integer n written in the second line, (1<=n<=15 000). It denotes the number of nuggets in the area of the Goldmine. In the following n lines there are written the coordinates of the nuggets. Each of these lines consists of two integers x and y, (-30 000<=x,y<=30 000), separated by a single space and denoting the x and the y coordinate of a nugget respectively.



The text file KOP.OUT should contain exactly one integer equal to the value of the most valuable lot of a given size.



For the input file KOP.IN:
1 2
0 0
1 1
2 2
3 3
4 5
5 5
4 2
1 4
0 5
5 0
2 3
3 2

the correct answer is the output file KOP.OUT: