How to get total pages of PDF with FPDF?

$pdf = new FPDF();
$pdf->AddPage();
$pdf->AddPage();
$nb = $pdf->PageNo();
$pdf->Output();

    // Get the file into path 
    $path = 'LargePDF.pdf';
    // Call a the function FunctionCountPages 
    $totalPageCount=  FunctionCountPages($path);;
    echo $totalPages;
    function FunctionCountPages($path) 
          {
              $pdftextfile = file_get_contents($path);
              $pagenumber = preg_match_all("/\/Page\W/", $pdftextfile, $dummy);
              return $pagenumber;
            }
//I hope this work for you