WinBatch Countdown

@echo off
title Counter
echo Start countdown at?
echo.
set /p counter=Num^>
if %counter%==0 goto Cfz
if %counter% LEQ 0 goto Error
cls
:Loop
echo Num: %counter%
timeout /T 1 /NOBREAK>>nul
set /a counter=%counter%-1
if "%counter%"=="0" echo Num: 0& goto EndLoop
goto Loop
:EndLoop
echo Fertig!
echo.
pause>>nul
exit
:Error
echo That is not a number.
pause>>nul
exit
:Cfz
echo You can not count down from the number 0 LOL.
pause>>nul
exit