using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
static class Program{
	const int mod=(int)1e9+7;
	const double eps=1e-11;
	static void Main(){
		Sc sc=new Sc();
		var s=sc.Ia;
		var a=new long[s[0]];
		var dp=new long[s[0]];
		for(int i = 0;i<s[0];i++) {a[i]=sc.La.Sum();}
		Spt spt=new Spt(a,false);
		for(int i = s[0]-1;i>=0;i--) {
			dp[i]=a[i];
			for(int j = i+2;j<s[0];j++) {dp[i]=Max(dp[i],a[i]+dp[j]-spt.Get(i+1,j-1));}
		}
		Console.WriteLine("{0}",dp.Max());
	}
}
public class Spt{
	private readonly long[][] d;
	private readonly int[] l;
	private Func<long,long,long> Fu;
	public Spt(long[] a,bool bo){
		int n=a.Length,m=(int)Log(n,2)+1;
		d=new long[m][];
		d[0]=new long[n];
		l=new int[n+1];
		if(bo){Fu=(y,x)=>Max(y,x);}
		else{Fu=(y,x)=>Min(y,x);}
		for(int i=0;i<n;i++){
			d[0][i]=a[i];
			l[i+1]=l[i>>1]+1;
		}
		for(int i=1,k=1;i<m;i++,k<<=1){
			int p=n+1-(k<<1);
			d[i]=new long[p];
			for(int j=0;j<p;j++){d[i][j]=Fu(d[i-1][j],d[i-1][j+k]);}
		}
	}
	public long Get(int a,int b){
		if(a>b){(a,b)=(b,a);}
		int p=l[b-a];
		return Fu(d[p][a],d[p][b+1-(1<<p)]);
	}
}
public class Sc{
	public int I{get{return int.Parse(Console.ReadLine());}}
	public long L{get{return long.Parse(Console.ReadLine());}}
	public double D{get{return double.Parse(Console.ReadLine());}}
	public string S{get{return Console.ReadLine();}}
	public int[] Ia{get{return Array.ConvertAll(Console.ReadLine().Split(),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Console.ReadLine().Split(),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Console.ReadLine().Split(),double.Parse);}}
	public string[] Sa{get{return Console.ReadLine().Split();}}
	public object[] Oa{get{return Console.ReadLine().Split();}}
	public int[] Ia2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),int.Parse);}}
	public int[] Ia3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),int.Parse);}
	public int[] Ia3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),long.Parse);}}
	public long[] La3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),long.Parse);}
	public long[] La3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),long.Parse);}
	public double[] Da2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),double.Parse);}}
	public double[] Da3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),double.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Console.ReadLine().Split());}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Console.ReadLine().Split());}return a;}
}