Upload Multiple Files with Accumulated

How to press choose file and selected let's say 2 files , then press choose and select 3 files so the total files to upload must be 5 file ?

 

ASPX

 

 

Aspx.cs

protected void UploadMultipleFiles(object sender, EventArgs e) {

 foreach (HttpPostedFile postedFile in FileUploadMultible1.PostedFiles) { string  fileName = postedFile.FileName;      postedFile.SaveAs(Server.MapPath("~/Media/") +fileName); }