Avid TV Watcher

Here is a TV avid person. He wants to spend his max time on TV. There are N channels with different program of different length and diff times. WAP so that the person can spend his max time watching TV.Precondition: If that person watches a program, he watches it completely.

Ex:
Channel1:
prog1 – 8:00- 8:30
prog2: 9:00 – 10:00
prog3: 10:15 – 12:00

channel2:
prg1 – 8:15 – 10:00
prg2: 10:30 – 12:00

So in this case max time will be if he watches:

ch2/prg1 + ch1/prg3