from random import randint
import sys
from sys import setrecursionlimit
from bisect import bisect_left
from collections import deque, defaultdict as dd
from heapq import *
from itertools import combinations
setrecursionlimit(1<<21)
if hasattr(sys, "set_int_max_str_digits"):
    sys.set_int_max_str_digits(0)


MOD = 1000000007

def main():
    _ = int(input())
    a = [int(x) for x in input().split()]
    if min(a)==0:
        print("-1")
        return
    elif max(a)>=4:
        print(MOD)
        return
    res = 1
    f = [1,1,2,6]
    for v in a:
        res *= pow(v, f[v])
        if res > MOD:
            print(MOD)
    print(MOD%res)


if __name__ == "__main__":
    main()