#include<cstdio>
#include<iostream>
using namespace std;
int n,a[100010];
int main()
{
	int i,j,x,y,poz1,poz2;
	long long sum,aux,maxim=-1;
	freopen("avioane.in","r",stdin);
	scanf("%d",&n);
	for(i=1;i<=n;i++)
		scanf("%d",&a[i]);
	sort(a+1,a+n+1);
	//for(i=1;i<=n;i++)
	//	cout<<a[i]<<' ';
	//cout<<"\n";
	for(i=1;i<n;i++)
	{
		for(j=i+1;j<=n;j++)
		{
			if(a[i]!=a[j])
			{
				x=a[i];
				y=a[j];
				poz1=lower_bound(a,a+n+1,x-1)-a-1;
				poz2=lower_bound(a,a+n+1,y-1)-a-1;
				poz2=n-poz2;
				poz1=n-poz1-poz2;
				//cout<<x<<' '<<poz1<<" ";
				//cout<<y<<' '<<poz2<<" ";
				sum=poz1;
				sum=sum*x;
				aux=poz2;
				aux=aux*y;
				sum=sum+aux;
				maxim=max(maxim,sum);
				//cout<<sum<<"\n";
			}
		}
	}
	freopen("avioane.out","w",stdout);
	printf("%lld\n",maxim);
	return 0;
}