Error 24, inputFolder.getFiles is not a function?

Question

i get this error when trying to run the script from photoshop.
can you please tell me what im doing wrong? Thanks!
#target photoshop
app.bringToFront();
var layoutNumber = prompt('Please Enter layout Number');
var parentFolder = "C:/Users/Rob/Desktop/Layout Drop/"
var inputFolder = parentFolder.concat(layoutNumber);
OpenFolder();
function OpenFolder() {
        var filesOpened = 0;
        var fileList = inputFolder.getFiles();
        for ( var i = 0; i < fileList.length; i++ ) {
                               // Make sure all the files in the folder are compatible with PS
                if ( fileList[i] instanceof File && ! fileList[i].hidden && ! filesToexclude( fileList[i], gFilesToSkip )) {
                        open( fileList[i] );
                        filesOpened++;
function filesToexclude( inFileName, inArrayOfFileExtensions ) {
          var lastDot = inFileName.toString().lastIndexOf( "." );
          if ( lastDot == -1 ) {
                    return false;
          var strLength = inFileName.toString().length;
          var extension = inFileName.toString().substr( lastDot + 1, strLength - lastDot );
          extension = extension.toLowerCase();
          for (var i = 0; i < inArrayOfFileExtensions.length; i++ ) {
                    if ( extension == inArrayOfFileExtensions[i] ) {
                              return true;
          return false;

Answer 1

ok so i'm a noob. i got it
#target photoshop
app.bringToFront();
var layoutNumber = prompt('Please Enter layout Number');
var inputFolder = Folder("C:/Users/Pro-012/Desktop/Drop/" + layoutNumber + "/");
OpenFolder();
function OpenFolder() {
        var filesOpened = 0;
        var fileList = inputFolder.getFiles();
        for ( var i = 0; i < fileList.length; i++ )
                    open(fileList[i])