my @letters=qw(A B C D);
print '    ';
    foreach my $key (@letters){          
        printf ("%s", $key);
    }
    
    "\n";
    
    foreach my $key (@letters) {
        print $key,' ';
        foreach my $key2 (@letters) {
            printf ("%.1f" , $A->{$key}->{$key2});
        }
        print "\n";
    }
}