List Of Folder Names Missing Leading Zeros

I have sub folders with names 0001, 003A, 0032 etc in a main folder. I am using the following code to copy these sub folders name to the worksheet column A. This works well except that folder 0001 is copied as 1, 0032 as 32. How to modify the code so that 0001 is displayed in column A instaed of 1.

Private Sub Workbook_Open()
Range("b3:b6500").Clear
Range("c3:c6500").Clear
Dim fs, F, f1, fc, s, i
Range(Cells(3, 1), Cells(6500, 1)).Clear
parentfolder = ThisWorkbook.Path
Set fs = CreateObject("Scripting.FileSystemObject")
Set F = fs.GetFolder(parentfolder)
Set fc = F.SubFolders
For Each f1 In fc
Cells(3 + i, 1) = f1.Name
i = i + 1
Next
End Sub