how to show lenghtmenu at topright corner?

$(document).ready(function() {
$('#example').DataTable( {
destroy: true,
lengthMenu: [[10, 25, 50, -1], [10, 25, 50, "All"]],
dom: 'Blfrtip',
buttons: [
'copy',
'csv',
'excel',
'pdf',
{
extend: 'print',
text: 'Print all (not just selected)',
exportOptions: {
modifier: {
selected: null
}
}
}
],
select: true
} );
} );