using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Numerics;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using static System.Math;
public static class P
{
    public static void Main()
    {
        int n = int.Parse(Console.ReadLine().Trim());
        var a = Console.ReadLine().Trim().Split().Select(int.Parse).ToArray();
        if (a.Contains(0))
        {
            Console.WriteLine(-1);
            return;
        }

        long res = 1;
        foreach (var item in a)
        {
            long factorial = 1;
            for (int i = 1; i <= item; i++)
            {
                factorial *= i;
                if (32 <= factorial) goto over;
            }
            
            for (int i = 0; i < factorial; i++)
            {
                res *= item;
                if (1000000007 < factorial) goto over;
            }
        }

        Console.WriteLine(1000000007 % res);
        return;
        over:;
        Console.WriteLine(1000000007);
    }
}