How many grafts would I need?

[goingquick]

Realized I should mention my age and family history of hair loss:

30 years old.
Both grandfather's had good heads of hair right up until their deaths. My father is close to 60 and while he started thinning out around 50 years old, he still has pretty good hair. Of his three brothers, only one lost their hair; said brother was pretty much bald by 30.