Can someone help me please?

I want to match criteria (individual employee names) with a range (list of all employees) to count how many 'individuals' were on shift on any given day. The criteria is not in contiguous cells and I think this is my problem?? The names of employees on shift (the criteria) are in Colums E2, G2, I2 and K2.

Lets say the range is a list of 10 employees on the second Tab called "Employees", I have tried something like this: -

=COUNTIF (Employees!A1:A10, "E2,G2,I2,K2") but it does not work - obviously because I know little in Excel

NB. An employee can do a 'double shift' e.g. their name can appear twice in one day if they work AM and PM, but I only want to match and count their name once as I just want to know how many people were on duty any given day.

There are a maximum of 31 rows as the data is recorded daily for each month but I can drag the formula (once I have it) to populate all rows.

Thank you