Keko has dots in a 2-D coordinate plane. He wants to measure the gap between the most distant two dots. To make the problem easier, Keko decided to change each dot's or coordinate to zero.
Help Keko calculate the distance!
The first line contains an integer, , the number of dots.
The next lines each contain the integer coordinates of the dots in fashion.
It is guaranteed that all dots are distinct, and either their or coordinate is equal to .
Print the distance between the most distant dots with an absolute error of, at most, .
In the sample, the most distant dots are located at and .
The distance between them is .