def cmb(n, r, p):
    if (r < 0) or (n < r):
        return 0
    r = min(r, n - r)
    return fact[n] * factinv[r] * factinv[n-r] % p

p = 10 ** 9 + 7
N = 10 ** 3  # N は必要分だけ用意する
fact = [1, 1]  # fact[n] = (n! mod p)
factinv = [1, 1]  # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1]  # factinv 計算用
 
for i in range(2, N + 1):
    fact.append((fact[-1] * i) % p)
    inv.append((-inv[p % i] * (p // i)) % p)
    factinv.append((factinv[-1] * inv[-1]) % p)
    
mod = 10**9 + 7
N = int(input())
p = list(map(int,input().split()))
front = 0
back = 0
eq = 0
for tp in p:
    if tp>50:
        front += 1
    elif tp < 50:
        back += 1
    else:
        eq += 1
        
cnt = 0
ans = 0
while 2*cnt+1 <= front:
    ans += cmb(front,2*cnt+1,mod)
    cnt += 1
    ans %= mod
    
ans *= pow(2,back+eq,mod)
print(ans%mod)