N = int(input())
e = []
for i in range(N):
    e.append(int(input()))
    
dp = [[[0] * 4 for _ in range(N)] for _ in range(4)]
for i in range(4):
    dp[i][1][i] = 1
    
S = [[0, 4, 7], [1, 2, 3, 5, 6]]
mod = 10 ** 9 + 7
for a in range(4):
    for n in range(2, N):
        for x in range(4):
            for i in range(2):
                now = x * 2 + i
                if now not in S[e[n - 1]]:
                    continue
                nx = now % 4
                dp[a][n][nx] += dp[a][n-1][x]
                dp[a][n][nx] %= mod
                
ans = 0
for a in range(4):
    for b in range(4):
        nx = b % 2 * 4 + a
        if nx not in S[e[0]]:
            continue
        nx = b * 2 + a // 2
        if nx not in S[e[-1]]:
            continue
        ans += dp[a][-1][b]
        ans %= mod
        
print(ans)