Diameter of a Convex Polygon

Find the diameter of a convex polygon g. In other words, find a pair of points that have maximum distance between them.

Input

n
x1 y1 
x2 y2
:
xn yn

The first integer n is the number of points in g.

In the following lines, the coordinate of the i-th point p_i is given by two real numbers x_i and y_i. The coordinates of points are given in the order of counter-clockwise visit of them. Each value is a real number with at most 6 digits after the decimal point.

Output

Print the diameter of g in a line. The output values should be in a decimal fraction with an error less than 0.000001.

Constraints

• 3 ≤ n ≤ 80000
• -100 ≤ x_i, y_i ≤ 100
• No point in the g will occur more than once.

Sample Input 1

3
0.0 0.0
4.0 0.0
2.0 2.0

Sample Output 1

4.00

Sample Input 2

4
0.0 0.0
1.0 0.0
1.0 1.0
0.0 1.0

Sample Output 2

1.414213562373

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