#!/usr/bin/perl -w

use strict;
use warnings;
use diagnostics;
use Data::Dumper;

my $filename = "dna.txt";
open(my $fh, "<", $filename) || die "could not open $filename: $!\n";

my %bases;
my $cnt_errors = 0;

while (<$fh>) {
    # strip spaces
    s/\s+//ig;
    # collect results
    my @results = ($_ =~ /[ACGT]/ig);
    map { $bases{$_}++ } @results;

    $cnt_errors += ( length($_) - scalar @results );
}


print Dumper(%bases);
print "Errors: $cnt_errors\n";