probability distribution question. help please !!

13. In the dice game Yahtzee, a player has three tries at rolling some or all of a set of five dice. Each player is trying to achieve results such as three-of-a-kind, two-pairs, full-house, and so on. A yahtzee occurs when a player rolls 5-of-a-kind. If Cheryl rolls a pair of 2s on the first toss, and then rolls only the non-2s showing on the subsequent two tosses, find the probability that she gets a yahtzee