if else condition with between operator

Hi,

I am using M language and adding a new column in table.

I need to write if condition in this line.

I am writing if condition like this:

if [Month] between 2 and 4 then "yes" else "no"

Now here I am getting error for between key word. 

Please tell me what is the error and what is the correct way of writng this condition.

Thanks

Rajneesh