/*
मनस्वी म्रियते कामं कार्पण्यं न तु गच्छति ।
अपि निर्वाणमायाति नानलो याति शीतताम् ॥
*/

#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp> 
// #include <ext/pb_ds/tree_policy.hpp> 
// using namespace __gnu_pbds;
using namespace std;
#define mod 1000000007
#define pb push_back
#define mp make_pair
#define ll long long int
#define ld long double
#define vi vector<int>
#define vl vector<ll>
#define v2i vector<vector<int>>
#define v2l vector<vector<ll>>
#define ppi pair<int,int>
#define ppl pair<ll,ll>
#define vpi vector<ppi>
#define vpl vector<ppl>
#define all(x) x.begin(),x.end()
#define ii int,int 
#define ff first    
#define ss second
#define forn(i,a,b) for(int i=a;i<b;i++)
#define forr(i,a,b) for(int i=a;i>=b;i--)
#define forv(i,m) for(auto i : m)
#define p2d(v) for(auto a:v){for(auto b:a)cout<<b<<" ";cout<<endl;}
#define p1d(v) for(auto a:v)cout<<a<<" ";cout<<endl;
#define ppd(v) for(auto a:v)cout<<a.ff<<" "<<a.ss<<endl;
#define imx INT_MAX
#define imn INT_MIN
#define inf 9000000000000000000
#define minf -inf
#define endl "\n"
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);
#define sze size()
#define rvs reverse 
#define itr iterator 
#define pre cout<<fixed<<setprecision(10);
#define umap unordered_map
#define uset unordered_set
#define pi 3.141592653589793
#define MAXN 100005
#define test1(x) cout << #x " = " << x << endl;
#define test2(x,y) cout << #x " = " << x << " " << #y " = " << y << endl;
#define test3(x,y,z) cout << #x " = " << x << " " << #y " = " << y << " " << #z " = " << z << endl;
#define test4(w,x,y,z) cout << #w " = " << w << " " << #x " = " << x << " " << #y " = " << y << " " << #z " = " << z << endl;
const ll infinity = 9e18;

/*
#define oset tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define MODM(a,b,md) ((a%md)*(b%md))%md
#define MODA(a,b,md) ((a%md)+(b%md))%md
#define ull unsigned long long int
*/

/*
bool compare(int a,int b) {return a > b;}
bool compare1(ppi a,ppi b) {return a.ff > b.ff;}
bool compare2(ppi a,ppi b) {return a.ss < b.ss;}
ll Npower(ll a,ll b) {ll product = 1; while(b){if(b&1){product = product*a;}a = a*a;b = b>>1;} return product;}
ll power(ll a,ll b,ll md) {ll product = 1; while(b){if(b&1){product = MODM(product,a,md);}a = MODM(a,a,md);b = b>>1;} return product%md;}
bool isprime(ll n){if(n < 2) return 0; ll i = 2; while(i*i <= n){if(n%i == 0) return 0; i++;} return 1;}
ll GCD(ll a,ll b) {return b==0 ? a:GCD(b,a%b);}
ll LCM(ll a,ll b) {return (a/GCD(a,b))*b; }
*/


int main()
{
    fast

/*
    #ifndef ONLINE_JUDGE
        freopen("input.txt",  "r",  stdin);
        freopen("output.txt", "w", stdout);
    #endif
//*/

        
    ll n;
    cin>>n;

    vl v(n);

    ll sum = 0;

    forn(i,0,n)
    {
        cin>>v[i];
        sum += v[i];
    }
        
    v2l dp(n,vl(n,0));

    forn(i,0,n)
    {
        dp[i][i] = v[i];
    }


    for(int len = 2; len <= n; len++)
    {
        for(int i = 0; i < n-len+1; i++)
        {
            int j = i+len-1;

            if(len == 2)
            {
                dp[i][j] = max(v[i],v[j]);
            }
            else
            {
                dp[i][j] = max(v[i]+min(dp[i+2][j],dp[i+1][j-1]),v[j]+min(dp[i][j-2],dp[i+1][j-1]));
            }

        }
    }

    cout<<(2*dp[0][n-1]-sum);


    return 0;
}   

Measured memory_bytes: 73676