N = int(input())
A = list(map(int, input().split()))
MOD = 10 ** 9 + 7
up, down = 0, 0
for a in A:
    if a > 50:
        up += 1
    elif a < 50:
        down += 1
if down:
    print((pow(2, up, MOD) * pow(2, down - 1, MOD)) % MOD)
else:
    print(0)