MOD = 10 ** 9 + 7
n = int(input())
p = list(map(int, input().split()))
dp1 = [0] * (n + 1)
dp2 = [0] * (n + 1)
dp1[0] = 1
ans = 0
for i in range(n):
    if p[i] > 50:
        dp2[i + 1] += dp1[i] + dp2[i]
        dp1[i + 1] += dp1[i] + dp2[i]
    elif p[i] < 50:
        dp1[i + 1] += dp1[i] * 2
        dp2[i + 1] += dp2[i] * 2
    else:
        dp1[i + 1] += dp1[i]
        dp2[i + 1] += dp2[i]
    dp1[i + 1] %= MOD
    dp2[i + 1] %= MOD
print(dp2[n])