Problem - Pulling Month of Last Purchase

Hello,

I am struggling with how to accomplish something I am trying to do, but I will describe as best as I can.

I have a series of columns arranged by Month after my leading column, which shows my accounts.

What I am trying to do is identify the last month that an account purchased a product. If they had never purchased anything, then the field will show "None"

I have no clue how to accomplish this in excel. Attached is an example of how the spreadsheet looks and what the column should show.

Any help here would be greatly appreciated.

Last Purchased Month - Example (1).xlsx