I'm sure there's a way to do this but just can't seem to get it. I have two separate lists in Excel. One is customer account numbers, of which there are 50, and one is part numbers, of which there are 350. Each account number only appears once and each part number only appears once.

I need to upload these to another program and so need to create an Excel sheet where in column A I have each account number listed and in column B I have each part number listed (meaning that each account number will be listed 350 times as there will be one row for each part number against that account number). In total there will be 17500 entries. What I'm trying to avoid doing is having to copy and paste to achieve this!

I'd appreciate any help :)