#include <FileConstants.au3>
#include <MsgBoxConstants.au3>
#include <WinAPIFiles.au3>
Local $hFileOpen = FileOpen("test.txt",$FO_READ +  $FO_OVERWRITE )
Local $sFileRead = FileReadLine($hFileOpen, 1)
Local $number = InputBox("ввод","введите число")
if (int($number) > int($sFileRead)) Then
Local $hFileOpen = FileOpen("test.txt",$FO_OVERWRITE)
FileWrite($hFileOpen,$number)
msgbox(0,"title",$number)
EndIf