my @letters=qw( A R N D);

 sub printMatrix1 {
    my ($A) = @_;
    foreach my $key (sort keys %$A) {
        print $key."  "x2;
        foreach my $key2 (sort keys %{$A->{$key} } )  {
            printf( "%.4f  " , $A->{$key}->{$key2} );
        }
        print "\n"x2;
    }
}