N = int(input())
A = list(map(int, input().split()))
if 0 in A:
    print(-1)
    exit()
M = 10**9 + 7
f = lambda x: 1 if x == 1 else x * f(x - 1)
ans = 1
for a in A:
    if a > 3:
        print(M)
        exit()
    ans *= a**f(a)
    if ans > M:
        print(M)
        exit()
print(M % ans)