use Socket;
use strict;
use warnings;

my %stat;
my @addr = qw(10.0.0.1
			  10.0.0.2
			  10.0.0.3
			  192.168.1.5
			  192.168.1.6
			  192.168.10.3
			  192.168.10.4
			  192.168.10.5);
$stat{inet_ntoa(substr(inet_aton($_), 0, 3) . "\0")} ++ foreach (@addr);
print "$_ has $stat{$_} nodes\n" foreach (keys %stat);