import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
static int gcd(int x,int y){
    if(y==0){
        return x;
    }else{
        return gcd(y,x%y);
    }
}
    static long maximumValue(int[] a) {
       Arrays.sort(a);
       int s=a[a.length-1];
        int s1=a[a.length-2];
        int g=gcd(s,s1);
       // System.out.println(g);
        long sum=s1+s;
     //   System.out.println(sum);
        long res=g*(sum-s);
        return res;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] a = new int[n];
        for(int a_i = 0; a_i < n; a_i++){
            a[a_i] = in.nextInt();
        }
        long result = maximumValue(a);
        System.out.println(result);
        in.close();
    }
}