n = int(input())
P = list(map(int, input().split()))
mod = 10**9+7
n0, n1 = 0, 0
for p in P:
    if p < 50:
        n0 += 1
    elif p > 50:
        n1 += 1
        
if n1 == 0:
    print(0)
else:
    ans = pow(2, n0+n1-1, mod)
    print(ans)