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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace  std;

int a[15];
int b[15];
int n;
int ans = 0;

void dfs(int i){
	if(i == n+1){
		int res = 1;
		for(int i=1;i<=n;i++) res*=b[i];
		if(res%2 == 0) ans++;
	}
	else{
		for(int j=a[i]-1;j<=a[i]+1;j++){
			int k = j%2;
			b[i] = j;
			dfs(i+1);
		}
	}
}

int main(){
	scanf("%d", &n);
	for(int i=1;i<=n;i++){
		scanf("%d", &a[i]);
	}
	dfs(1);
	printf("%d\n", ans);
}