#!/usr/bin/perl

use strict;
use warnings;

my $regex_cache = {};

die "Usage $0 [CAC <NUM> TTT <NUM>]\n" if ( @ARGV % 2 );
my %input = @ARGV; # Where the input would be : CAC 2 TTT 2

my $data_set = <DATA>;

for my $in ( keys %input ) {
    my $reg_key = "($in)\{$input{$in}\}";
    my $reg = $regex_cache->{$in} ||= qr/($reg_key)/s;
    print "$1\n" if ( $data_set =~ $reg );
}

__DATA__
ATCACCACTTCCTGGACACTACCCTAAACCTTTGAGGA
AATAACCGCTTTGTTGTTGCGATCGCCTAATAAATATC
AGCGTCTTCGTATGATAAACCAATGCGGAAGTACAAAA


##</code><code>##

print$_ for(map{chr($_)}split(/\s+/,join(/\B?:\w+[^\s+]/,<DATA>)));
__DATA__
67 111 100 101 32 80 101 114 108