import sys
input = lambda : sys.stdin.readline().rstrip()

write = lambda x: sys.stdout.write(x+"\n")
debug = lambda x: sys.stderr.write(x+"\n")
writef = lambda x: print("{:.12f}".format(x))


n = int(input())
p = list(map(int, input().split()))
M = 10**9+7
inv2 = pow(2, M-2, M)
dp = [1,0,0] # (0.5未満, 0.5, 0.5以上)
for v in p:
    ndp = dp[:]
    if v<50:
        for i in range(3):
            ndp[i] += dp[i]
            ndp[i] %= M
    elif v>50:
        for i in range(3):
            ndp[2-i] += dp[i]
            ndp[2-i] %= M
    else:
        ndp[1] += sum(dp)
        ndp[1] %= M
    dp = ndp
ans = dp[2]
print(ans%M)