Hi, I need some help with this...

Two dice are rolled until a 6 appears on at least one of the dice. What is the probability that it takes at least four rolls(of two dice) before the first 6 is obtained?

Is this a binomial process: X~B(4, 2/12)

P(X >= 4) = 1 - [f(0)+f(1)+f(2)+f(3)] ?????

Thanks