# Trip

Time Limit: 1 Second Memory Limit: 32768 KB

Angel's holiday has come. Angel wants to go on a nice trip with c.x. by sea, and there are so many choices. But Angel doesn't have much money, so he can only go from one place to another with c.x. He wants to go as far as he can.We assume that there are N (1 <= n <= 30000) cities in the country. And Angel is at one of them. Every city is represented as a point (x, y), where 0 <= x, y <= 32000. Angel can start at any point and end at any point. You must find the longest distance between two points.

## Input

For each testcase, first line contains one integer N. Then N lines followed.
Every line contains two integers (x, y).

Proceed to the end of file.

## Output

For each testcase, you should output the longest distance, having 2 digits after radix point.

## Sample Input

4 0 0 1 1 0 1 1 0

## Sample Output

1.41Submit

Source: JIANG, Yanyan's Contest #1