Problem:
Score : 200 points

Problem Statement

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?

Constraints

1 \leq N \leq 10

1 \leq A_i \leq 100

Input

Input is given from Standard Input in the following format:

N
A_1 A_2 ... A_N

Output

Print the number of integer sequences that satisfy the condition.

Sample Input 1

2
2 3

Sample Output 1

7

There are seven integer sequences that satisfy the condition:

1, 2

1, 4

2, 2

2, 3

2, 4

3, 2

3, 4

Sample Input 2

3
3 3 3

Sample Output 2

26

Sample Input 3

1
100

Sample Output 3

1

Sample Input 4

10
90 52 56 71 44 8 13 30 57 84

Sample Output 4

58921

Solution in Pascal (FPC 2.6.2) (judge verdict: Accepted)

var n,i,j,ans:longint;
var a,r,b:array[0..1000] of longint;
var f:array[0..1000,0..1000] of longint;
procedure dfs(d:longint);
var i,j:longint;
var a1:int64;
begin
  if d>n then begin
  a1:=1;
    for i:=1 to n do
    begin if abs(a[i]-b[i])>1 then exit;a1:=a1*a[i];end;
 if a1 mod 2=0 then     inc(ans);
    exit;
  end;
    a[d]:=b[d];dfs(d+1);
    a[d]:=b[d]-1;dfs(d+1);
    a[d]:=b[d]+1;dfs(d+1);
end;
begin
  read(n);
  for i:=1 to n do read(b[i]);dfs(1);
  writeln(ans);
end.