using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution
{

    static long maximumValue(int[] a)
    {
        long? max = null;
        for (int i = 0; i < a.Length; i++)
            for (int j = 0; j < a.Length; j++)
            {
               // Console.WriteLine($"{GCD(a[i], a[j])} * ({a[i] + a[j]} - {(a[i] > a[j] ? a[i] : a[j])})");

                var m = GCD(a[i], a[j]) * ((i == j ? a[i] : a[i] + a[j]) - (a[i] > a[j] ? a[i] : a[j]));
                //Console.WriteLine($"{i} {j} :{m}");
                if (max == null || max < m)
                    max = m;
            }
        return max.Value;
    }

    public static long GCD(int p, int q)
    {
        p = Math.Abs(p);
        q = Math.Abs(q);
        if (q == 0)
        {
            return p;
        }

        int r = p % q;

        return GCD(q, r);
    }

    static void Main(String[] args)
    {
        int n = Convert.ToInt32(Console.ReadLine());
        string[] a_temp = Console.ReadLine().Split(' ');
        int[] a = Array.ConvertAll(a_temp, Int32.Parse);
        long result = maximumValue(a);
        Console.WriteLine(result);
        //Console.ReadKey();
    }
}