How can I configure the script not to create a new file if the original file is not present?

I need to modify the following script so that if it can't find the original.txt file it will not create a newdatafile.txt

$InputFile = "C:\Programs\Temp\original.txt"
$OutputFile = "C:\Programs\Temp\newdatafile.txt"

Function ParseText ($OutputFile,$InputFile){
Begin{
$poline,$totline,$total = $NULL,$NULL,$NULL
Set-Content $OutputFile $null
}
Process{
      Get-Content -Path $InputFile | % {

If ($_ -match "AZI\*1"){
      If ($poline -ne $null -and $total -ne $null){
      $Totline = "Total: `$$Total"
      write-host "This is Total `$$total"
            "`n$poline `r`n$totline" | out-file $OutputFile -Encoding UTF8 -Append
            $poline,$totline,$total = $NULL,$NULL,$NULL
      }
}
   If($_ -match "(MA\*)(\d{0,10})") {
      $poline = "PONumber: $($Matches[2])"
    }Elseif ($_ -match "PO1"){
        $col=$_.split("*") ; $total += [double]$col[2] * [double]$col[4]
  }
 }
}
}

ParseText $OutputFile $InputFile


Currently, this will produce the new file regardless if it finds the input file or not.

It must not create the new file if the input file does not exist.