The Department of National Defence (DND) wishes to connect
several northern outposts by a wireless network. Two different
communication technologies are to be used in establishing the
network: every outpost will have a radio transceiver and some
outposts will in addition have a satellite channel.
Any two outposts with a satellite channel can communicate
via the satellite, regardless of their location. Otherwise, two
outposts can communicate by radio only if the distance between
them does not exceed $D$,
which depends of the power of the transceivers. Higher power
yields higher $D$ but
costs more. Due to purchasing and maintenance considerations,
the transceivers at the outposts must be identical; that is,
the value of $D$ is the
same for every pair of outposts.
Your job is to determine the minimum $D$ required for the transceivers.
There must be at least one communication path (direct or
indirect) between every pair of outposts.
Input
The first line of input contains $N$, the number of test cases. The
first line of each test case contains $1 \le S \le 100$, the number of
satellite channels, and $S < P
\le 500$, the number of outposts. $P$ lines follow, giving the
($x,y$) coordinates of
each outpost in km (coordinates are integers between
$0$ and $10\, 000$).
Output
For each case, output should consist of a single line giving
the minimum $D$ required
to connect the network. Output should be specified to
$2$ decimal points.
Sample Input 1 
Sample Output 1 
1
2 4
0 100
0 300
0 600
150 750

212.13
