Probability of a probability?

Probability Level 4

You have an unfair coin with probability $p$ of landing on heads. This probability is a random variable uniform in the interval $[0,1]$ .

Now, you flip it and get heads. What is the probability that $p>\frac{1}{2}$ ?

0 1/3 1/2 5/8 2/3 3/4 1 It can't be determined