counting weekendshifts

[leo]

In the shifts-planning workbook I created I have
12 monthly worksheets and a summary sheet.
Each monthly sheet has the dates in row D3..AH3 (jan 1 -
jan 31)
The employees in column A4..A31 (john, frank, pete etc)
Each shift is coded in letters A, B, N, IC, GIP, etc.(per
employee under the date (s)he's on duty)

I have totalled all the shifts per month per employee in
the summary page. To see how that matches their contract.
Next thing I want is for each employee to list on the
summary page the number of shifts made in a weekend, each
month.

Can I do that? How?

Thanks