Formula to summarize data

[rizmomin]

Hello:

Please refer to attached file.
I have 2017, 2016 data for Store1, Store2 etc as shown in tabs
Data for 2017 start in row 2 thru row 366 for items list in Row1
Data for 2016 start in row 401 thru row 766.

I need formula to summarize the data as below:

Select YTD Sheet.
Will select Store from dropdown in cell B2.
I have listed items in cell C2,D2,E2.
I need summary for each item for each month for selected store for 2017:Jan,Feb....and 2016:Jan, Feb etc in cell C4:E15 and C20:E31.


Let me know if you have any questions.
Thanks.

Riz