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

public class Solution {
	static public int GCD(int a, int b) {
		if(a<0)
			a=a*-1;
		if(b<0)
			b=b*-1;
		if (b==0) return a;
		   return GCD(b,a%b);
	}
	
	static public int sum(int a,int b){
        if(a==b)
			return a;
		return a+b;
	}
	
	static public int max(int a,int b){
		if(a>b)
			return a;
		else if(b>a)
			return b;
		else 
			return a;
	}
	
	static public int functionOfLnR(int a,int b){
		int value=0;
		value=GCD(a,b)*(sum(a,b)-max(a,b));
		return value;
	}
	
	static long maximumValue(int[] a) {
        int maxVal=0;
        for(int i=0;i<a.length;i++){
        	for(int j=0;j<a.length;j++){
        		int temp=GCD(a[i],a[j]);
        		if (temp>maxVal) {
					maxVal=temp;
				}
        		temp=sum(a[i],a[j]);
        		if (temp>maxVal) {
					maxVal=temp;
				}
        		temp=max(a[i],a[j]);
        		if (temp>maxVal) {
					maxVal=temp;
				}
        		temp=functionOfLnR(a[i],a[j]);
        		if (temp>maxVal) {
					maxVal=temp;
				}
        	}
        }
        return maxVal;
    }

    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();
    }
}