use strict;
use warnings;

my %mags;
while (<DATA>) {
    next if /X/;
    chomp;
    my $pair = (split)[-1];
    my ($time, $mag) = split /,/, $pair;
    $time =~ s/\..*//;
    $mags{$time}{$mag} = $_;
}

for my $time (sort keys %mags) {
    my $mag = (sort {$b <=> $a} keys %{ $mags{$time} })[0];
    print "$mags{$time}{$mag}\n";
}

__DATA__
X,Y,Z,Time,Amplitude
2550,531,66,10-12-2007 07:03:08.069,2
2549,529,62,10-12-2007 07:03:08.151,1
2550,531,66,10-12-2007 07:03:09.069,1
2549,529,62,10-12-2007 07:03:09.151,2