MOD = 10**9 + 7

N = int(input())
P = list(map(int, input().split()))

a_count = 0  # number of coins with p_i < 50 (s_i = +1)
b_count = 0  # number of coins with p_i > 50 (s_i = -1)

for p in P:
    if p < 50:
        a_count += 1
    elif p > 50:
        b_count += 1

if b_count == 0:
    print(0)
else:
    # The answer is 2^(a_count + b_count - 1) mod MOD
    exponent = a_count + b_count - 1
    print(pow(2, exponent, MOD))