from math import factorial
N = int(input())
A = list(map(int, input().split()))
A.sort()
if 0 in A:
    ans = -1
elif max(A) >= 4:
    ans = 10**9+7
else:
    product = 1
    for a in A:
        product *= pow(a, factorial(a))
    ans = (10**9+7)%product
print(ans)