n = int(input())
p = list(map(int, input().split()))
und, ovr = 0, 0
for i in range(n):
	if p[i] > 50: ovr += 1
	if p[i] < 50: und += 1
if ovr == 0: print(0)
else: print(pow(2, ovr + und - 1, 10 ** 9 + 7))