In these quarantine days, a list of what Max may do on a typical day is given in a table with the starting hour to ending hour.
Task Start End Sleep 0 6 Walk 6 7 Breakfast 8 9 Movie 10 16 Study 15 21 Dinner 22 23
Now Max wants to perform the maximum amount of tasks in a single day. How should he make his routine?
For this problem -- just return the number of tasks.