Validation in user input in batch script

I need to insert the validation in my batch script.When user enter the value it should be numeric+minimum length should be

2

for e.g.

02,03 

if he puts

1a,1A,2a3 

t hen should print the message that it is wrong and print te message enter valid value.

 
Echo RC is in format of 02
set  /p RC="enter RC Number Please : "
Echo Release Count is : %RC%

To check if numeric:

SET /A EV=RC
if %EV% EQU %RC% (
	echo Numeric
) else (
	echo Non-numeric
)

To compute length:

echo.%RC%>len
for %%a in (len) do set /a len=%%~za -2
echo %len%

Thanks for your kind Support