#include<iostream>

#include<cstring>

#include<cstdio>

#include<algorithm>

#define int long long

using namespace std;

inline int read(){

    int f=,ans=;char c=getchar();

    while(c<''||c>''){if(c=='-')f=-;c=getchar();}

    while(c>=''&&c<=''){ans=ans*+c-'';c=getchar();}

    return f*ans;

}

const int N=;

int dp[N][N],n,val[N],maxn;

int dfs(int l,int r){

    if(l==r) return dp[l][r]=val[l];

    if(l+==r) return dp[l][r]=max(val[l],val[r]);

    if(dp[l][r]!=-) return dp[l][r];

    int res=;

    if(val[l+]>val[r]) res=max(res,dfs(l+,r)+val[l]);

    else res=max(res,dfs(l+,r-)+val[l]);

    if(val[l]<val[r-]) res=max(res,dfs(l,r-)+val[r]);

    else res=max(res,dfs(l+,r-)+val[r]);

    return dp[l][r]=res;

}

signed main(){

    memset(dp,-,sizeof(dp));

    n=read();

    for(int i=;i<=n;i++) val[i]=val[i+n]=read();

    for(int i=;i<=n+;i++){

        maxn=max(maxn,dfs(i,i+n-));

    }

    printf("%lld\n",maxn);

}