You perform a radom experiment where a coin, with probability for heads p, is tossed until you observe the first heads.

Calculate a maximum likelihood estimate for p, provided than repeating the experiment four times gave the following results:

First repetition - heads observed on the 2nd toss;

Second repetition - heads observed on the 3rd toss;

Third repetition - heads observed on the 3rd toss;

Fourth repetition - heads observed on the 5th toss.