Postal Rotating Days

I'm postal worker, we have rotating day off. For example we have A,B,C,D,E,F days assigned to every postal carrier. And these rotates for example if i have day A and our week starts from Saturday, this week i have Monday my day off, so by default next week it will be Tuesday and then Wednesday and follows up. On Friday, we get Friday and Saturday together.
It works like that.
A. Monday
A. Tuesday
A. Wednesday
A. Thursday
A. Friday
A. Satuday
A. Monday follows up
And we really need this app to track hours.