#include <bits/stdc++.h>

using namespace std;



int main() {
    int n;
    cin >> n;
    int a[9000],max=0,agcd=0,b[900][900];
    for(int i = 0; i < n; i++){
       cin >> a[i];
    }
     
     for(int i = 0; i < n; i++){
        for(int j = i; j < n; j++){
            {while(a[i] != a[j])
    {
        if(a[i] > a[j])
            a[i] -= a[j];
        else
            a[i] -= a[j];
    }

    agcd=a[i];
    
}
            int sum=a[i]+a[j];
            if(a[i]>a[j])
                max=a[i];
            else
                max=a[j];
            int f=agcd*(sum-max);
            b[i][j]=f;
            
}}
    int super=0;
    for(int i=0;i<n;i++)
        for(int j=0;j<n;j++)
            if(super<b[i][j])
                super=b[i][j];
    cout<<super;
    
    
    return 0;
}