use strict;
use warnings;

my $rot = 6;

my $src = join '', 'a'..'z';
my $dst = substr($src, $rot) . substr($src, 0, $rot);

my $tr = eval "sub {
   local \$_ = \@_ ? \$_[0] : \$_;
   tr/$src/$dst/;
   return \$_;
}";

chomp(my $message = lc(<>));
$message = $tr->($message);
print("$message\n");