use strict;
use warnings;

my @letters = qw (A B C D E F);
my $string = "AFTYUBEWTWECRTUTYIYTDDDDRYJURTHJTREEEEEFGSDFF";
my $count;
foreach my $a(@letters) {
	eval "\$count = \$string =~ tr/$a//";
	print "$count\n";
}

##</code><code>##

$count = $string =~ s/$a//g;

##</code><code>##

my %count;
$count{$_}++ foreach split //, $string;
print "$count{$_}\n" foreach (@letters);