One rectangle

In the square 0 ≤ x ≤ 100, 0 ≤ y ≤ 100 there are n points with integer coordinates. You should find out rectangle which has no any of given point inside and has maximum possible area.

Remark: Points are permitted to be on the border of the rectangle.

Input

First line has the number n (1 ≤ n ≤ 100), next n lines has coordinates of n points.

Output

Your program should output one number - maximum area.

Examples