When should I go to bed?

Seeing as it is the end of the weekend I would love a believable excuse for staying up later than usual even though I still have to wake up at 8:00. So I let math convince me. This series of functions I formulated will let you deduce when you should go to bed:

First you will have to convert the time you woke up and the time you will be waking up tomorrow into a different format:

F(v,u) = 60v + u
Where: v = hours (military), u = minutes

I woke up at 2:30 so that equals 870 and I plan on waking up at 8, which equals 480. Now you will have to figure out what the time to go to sleep will be in the same format:

G(w,x) = x - [(1440-w+x)/3]
Where: w = time you woke up (converted), x = time to wake up (converted)

1440 - 870 + 480 = 1050
1050/3 = 350
480-350 = 130, which is the time I will be going to bed

H(y) = └y/60┘ , y - (└y/60┘ * 60)
Where: y = time to go to sleep (converted)

My answer would be: 2 , 10
The time I'm going to bed. :D

Btw: └3.23┘ = 3
It just removes the decimal place/fraction.