Score : 200 points
We will say that two integer sequences of length N, x_1, x_2, ..., x_N and y_1, y_2, ..., y_N, are similar when |x_i - y_i| \leq 1 holds for all i (1 \leq i \leq N).
In particular, any integer sequence is similar to itself.
You are given an integer N and an integer sequence of length N, A_1, A_2, ..., A_N.
How many integer sequences b_1, b_2, ..., b_N are there such that b_1, b_2, ..., b_N is similar to A and the product of all elements, b_1 b_2 ... b_N, is even?
Input is given from Standard Input in the following format:
N A_1 A_2 ... A_N
Print the number of integer sequences that satisfy the condition.
2 2 3
7
There are seven integer sequences that satisfy the condition:
3 3 3 3
26
1 100
1
10 90 52 56 71 44 8 13 30 57 84
58921