Count Instances off Absenses

I need a formula to count instances off Absence over the last year.
I.e. 1 day off is 1 absence, 4 days is 1 instance, 20 days is 1 instance etc etc.
Been trying to do it with the Weekday function but the problem is that only a 4 day week is worked so the Friday does not join up instances over subsequent weeks.
The dates are in Column E and the formulas I have tried and failed with are in K2

Thanks in advance.