How to create a formula to get the month name based on userresponse

Hi,

I have created a report using E-Fashion - Actually i need a report like - For ex i need 4 months data from 12 months

My report should display the 4 months data along with starting & end month data in the next 2 columns

I have used the prompt to fetch the data & i have created a formula in the cloumn like below:

For the column haader i have given = Tonumber(userresponse("Enter start:")) - I am getting the Month number in the header But i need the month name in the header.Please guide me

Regards

Karthika