Jigsaw puzzle is a popular intellectual game for its . It is not only used for education and entertainment, but also for commercial advertising and political propaganda.Maps,animal landscapes, characters, etc. can be made into jigsaw puzzles.

A salesman named Dimma began to sell jigsaw puzzles. It first partitioned a map into several rectangular tiles, then disrupt the order. You need to rearrange it, spell out the original map.

Suppose each fragment is a rectangle of a*b , Dimmaneeds to cut their printing costs by minimizing the number ofrectangleused for their maps.

The left side of Figure J-1 shows 8rectangles tocover a map. The right side shows how you can

cover the same map with only 6rectangles.

* Line 1: n a b (3 ≤ n ≤ 50 1 ≤ a, b ≤ 100)

n is the number of polygon vertices , a and b are the dimensions of eachrectangle.

*Line 2~ n+1: xi yi (0≤ xi≤ 10*a 0≤ yi≤ 10*b i=1…. n)

Each of the next n lines contains two integers xi nad yi specifying the vertices of the polygon representing the region (in either clockwise or counter-clockwise order).

print the minimal number of tiles necessary to cover the whole interior of the polygon.