#include<bits/stdc++.h>
using namespace std;
const int N=4010;
int sum[N],dp[N][N];
int n;
int dp_max(){
	int ans=0;
	for(int i=1;i<=n;i++) dp[i][i]=0;
	for(int len=2;len<=2*n;len++){
		for(int i=1;i<=n*2-len-1;i++){
			int j=i+len-1; 
				dp[i][j]=max(dp[i+1][j],dp[i][j-1])+sum[j]-sum[i-1];
		}
	}
	for(int i=1;i<=n;i++){
		ans=max(ans,dp[i][i+n-1]);
	}
	return ans;
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>sum[i];sum[i+n]=sum[i];
	}
	for(int i=1;i<=2*n;i++) sum[i]+=sum[i-1];
	cout<<dp_max();
	return 0;
}

/**************************************************************
	Problem: 2117
	User: liangshinan
	Language: C++
	Result: Accepted
	Time:248 ms
	Memory:65056 kb
****************************************************************/