#include <bits/stdc++.h>

using namespace std;

int gcdoftwo(int a, int b)
{
    if (a == 0 || b == 0)
       return 0; 
    if (a == b)
        return a;  
    if (a > b)
        return gcdoftwo(a-b, b);
    return gcdoftwo(a, b-a);
}

long maximumValue(vector <int> a) 
{
    // Return the maximum value of f among all subsegments [l..r].
    long sum,gcd,max,fun;
    long maximum;
    for(int i=0;i<a.size();++i)
    {
        for(int j=i;j<a.size();++j)
        {
            long gcd1=a[i],gcd2=a[j];
            max=a[i];
            if(a[j] > max)
                max=a[j];
            if(i == j)
                sum=a[i];
            else
                sum=a[i]+a[j];
            if(gcd1 < 0)
                gcd1=gcd1+(-(gcd1))+(-(gcd1));
            if(gcd2 < 0)
                gcd1=gcd2+(-(gcd2))+(-(gcd2));
            gcd=gcdoftwo(gcd1,gcd2);
                        
           fun=gcd*(sum-max);
           // cout<<"i : "<<i<<" j : "<<j<<endl;
          //  cout<<"max : "<<max<<" sum : "<<sum<<" gcd : "<<gcd<<endl;
          //  cout<<" fun : "<<fun<<endl;
            if(fun > maximum)
                maximum=fun;
        }
         
       // cout<<" maximum : "<<maximum<<endl;
    }
    return maximum;
}

int main() {
    int n;
    cin >> n;
    vector<int> a(n);
    for(int a_i = 0; a_i < n; a_i++){
       cin >> a[a_i];
    }
    long result = maximumValue(a);
    cout << result << endl;
    return 0;
}