A1036 | Moocast--Silver

Farmer John's $N$ cows ($1 \leq N \leq 1000$) want to organize an emergency
"moo-cast" system for broadcasting important messages among themselves.
Instead of mooing at each-other over long distances, the cows decide to equip
themselves with walkie-talkies, one for each cow. These walkie-talkies each
have a limited transmission radius, but cows can relay messages to one-another
along a path consisting of several hops, so it is not necessary for every cow
to be able to transmit directly to every other cow.
The cows need to decide how much money to spend on their walkie-talkies. If
they spend \$X, they will each get a walkie-talkie capable of transmitting up
to a distance of $\sqrt{X}$. That is, the squared distance between two cows
must be at most $X$ for them to be able to communicate.
Please help the cows determine the minimum integer value of $X$ such that a
broadcast from any cow will ultimately be able to reach every other cow.

The first line of input contains $N$.
The next $N$ lines each contain the $x$ and $y$ coordinates of a single cow.
These are both integers in the range $0 \ldots 25,000$.

Write a single line of output containing the integer $X$ giving the minimum
amount the cows must spend on walkie-talkies.