P = 10 ** 9 + 7
n = int(input())
a = list(map(int, input().split()))
if 0 in a:
    print(-1)
    exit()
now = 1
for x in a:
    x0 = x
    t = 1
    while x:
        t *= x
        if t > P:
            print(P)
            exit()
        x -= 1
    while t:
        now *= x0
        if now > P:
            print(P)
            exit()
        t -= 1
print(P % now)