Beauty Contest

Bessie, Farmer Ran's prize cow, has just won first place in a bovine
beauty contest, earning the title 'Miss Cow World'. As a result, Bessie
will make a tour of N (2 <= N <= 50,000) farms around the world in order
to spread goodwill between farmers and their cows. For simplicity, the
world will be represented as a two-dimensional plane, where each farm is
located at a pair of integer coordinates (x,y), each having a value in the
range -500,000,000 ... 500,000,000.  No two farms share the same pair
of coordinates.

Even though Bessie travels directly in a straight line between pairs of
farms, the distance between some farms can be quite large, so she wants to
bring a suitcase full of hay with her so she has enough food to eat on each
leg of her journey. Since Bessie refills her suitcase at every farm she
visits, she wants to determine the maximum possible distance she might need
to travel so she knows the size of suitcase she must bring. Help Bessie by
computing the maximum distance among all pairs of farms.

PROBLEM NAME: beauty

INPUT FORMAT:

* Line 1: A single integer, N.

* Lines 2..N+1: Two space-separated integers x and y specifying the
        coordinates of each farm.

SAMPLE INPUT:

4
0 0
0 1
1 1
1 0

OUTPUT FORMAT:

* Line 1: A single integer that is the _squared_ distance between the
        pair of farms  that are farthest apart from each other.

SAMPLE OUTPUT:

2

OUTPUT DETAILS:

Farm 1 (0, 0) and farm 3 (1, 1) have the
longest distance (square root of 2)