#include<fstream>
using namespace std;
ifstream in("expresie.in");
ofstream out("expresie.out");
long long v[1002];
int main()
{
	long long s=0, s1=0;
	int n, i, j;
	in >> n;
	for(i=1;i<=n;i++)
	{
		in >> v[i];
		s+=v[i];
	}
	for(i=3;i<=n;i++)
		if(s-(v[i-2]+v[i-1]+v[i])+v[i-2]*v[i-1]*v[i]>s1)
			s1=s-(v[i-2]+v[i-1]+v[i])+v[i-2]*v[i-1]*v[i];
	for(i=1;i<n;i++)
		for(j=1;j<n;j++)
			if(s-(v[i]+v[i+1]+v[j]+v[j+1])+v[i]*v[i+1]+v[j]*v[j+1]>s1 && j!=i)
				s1=s-(v[i]+v[i+1]+v[j]+v[j+1])+v[i]*v[i+1]+v[j]*v[j+1];
	out << s1;
	in.close();
	out.close();
	return 0;
}