open FILEIN, "list_contaminates.txt";
my %plates=();
my $total;
while(<FILEIN>){
    if(/^\s*([a-z0-9]+[a-z])([0-9]+)[a-z]+[0-9]+$/){ 
	$plates{$1}{$2}++; 
	$total++;
    }
    else{
	print "$_ not matched\n";
    }
} 
close FILEIN; 

print "$total contaminants\n";
my $lib; 
foreach $lib (keys %plates){
    my $to_print='';
    my $count=0;
    foreach (sort {$a <=> $b} keys %{$plates{$lib}}){
	$to_print.="\tplate $_: $plates{$lib}{$_} contaminants\n";
	$count+=$plates{$lib}{$_};
    }
    print "$lib - $count contaminants:\n$to_print"; 

}