import java.util.*;
public class Main {
public static void main(String args[]) {
Scanner sc=new Scanner(System.in);
int n=sc.nextInt();
int arr[]=new int[n];
for(int i=0;i<n;i++){
arr[i]=sc.nextInt();
}
System.out.println(GameStrategy(arr,0,n-1,0,0));
}
public static long GameStrategy(int arr[],int first,int last,long sum,long max ){
if(first>last){
if(sum>=max){
max=sum;
}
return max;
}
if(last<first){
if(sum>=max){
max=sum;
}
return max;
}
max=GameStrategy(arr,first+2,last,sum+arr[first],max);
max=GameStrategy(arr,first,last-2,sum+arr[last],max);
return max;
}
}