#include<iostream>
#include<cstdio>
using namespace std;
 
const int maxn=4005;
 
int n,a[maxn],s[maxn];
int f[maxn][maxn];
int nmax=0,tot;
 
void dp(){
	for(int d=2;d<=n;d++){
		for(int i=1;i<=2*n-d+1;i++){
			int zd=i+d-1;
			f[i][zd]=max(f[i+1][zd],f[i][zd-1]);
			f[i][zd]+=s[zd]-s[i-1];
		}
	}
	for(int i=1;i<=n;i++)
		nmax=max(f[i][n+i-1],nmax);
	cout<<nmax;
}
 
int main()
{
	freopen("stone3.in","r",stdin);
	freopen("stone3.out","w",stdout);
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		a[n+i]=a[i];
	}
	for(int i=1;i<=2*n;i++)
		s[i]=s[i-1]+a[i];
	dp();
}