toughest question i face in probability

X and Y are two chess players. The probability of X winning a particualr game against Y is $$\frac 13$$ and probability of Y winning the game is $$\frac 23$$.They play a series in which rules are such that if X wins 2 consecutive games then X wins the series and Y wins the series if Y wins 4 consecutive games. They start the game and play until one of them wins the series. Following these rules, the probability of Y winning the series is $$P$$. Then find $$258P$$.

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