MOD = 10 ** 9 + 7

n = int(input())
plst = list(map(int, input().split()))
cnt1 = sum(p > 50 for p in plst)
cnt2 = sum(p < 50 for p in plst)
if cnt2:
    print(pow(2, cnt1 + cnt2 - 1, MOD))
else:
    print(0)