1791: NBA Finals

Consider two teams, Lakers and Celtics, playing a series of NBA Finals until one of the teams wins n games. Assume that the probability of Lakers winning a game is the same for each game and equal to p and the probability of Lakers losing a game is q = 1-p. Hence, there are no ties.Please find the probability of Lakers winning the NBA Finals if the probability of it winning a game is p.

First line input the n-games (7<=n<=165)of NBA Finals! Second line input the probability of Lakers winning a game p (0< p < 1).

the probability of Lakers winning the NBA Finals. The answer should be given with an absolute or relative error of at most 10^-6.

7
0.4

0.289792

Special judge problem, you may get "Wrong Answer" when output in wrong format.