#include <bits/stdc++.h>
using namespace std;
void getre() {
  int x = 0;
  printf("%d\n", 1 / x);
}
void gettle() {
  int res = 1;
  while (1) res <<= 1;
  printf("%d\n", res);
}
template <typename T, typename S>
inline bool upmin(T &a, const S &b) {
  return a > b ? a = b, 1 : 0;
}
template <typename T, typename S>
inline bool upmax(T &a, const S &b) {
  return a < b ? a = b, 1 : 0;
}
template <typename N, typename PN>
inline N flo(N a, PN b) {
  return a >= 0 ? a / b : -((-a - 1) / b) - 1;
}
template <typename N, typename PN>
inline N cei(N a, PN b) {
  return a > 0 ? (a - 1) / b + 1 : -(-a / b);
}
template <typename N>
N gcd(N a, N b) {
  return b ? gcd(b, a % b) : a;
}
template <typename N>
inline int sgn(N a) {
  return a > 0 ? 1 : (a < 0 ? -1 : 0);
}
inline void gn(long long &x) {
  int sg = 1;
  char c;
  while (((c = getchar()) < '0' || c > '9') && c != '-')
    ;
  c == '-' ? (sg = -1, x = 0) : (x = c - '0');
  while ((c = getchar()) >= '0' && c <= '9') x = x * 10 + c - '0';
  x *= sg;
}
inline void gn(int &x) {
  long long t;
  gn(t);
  x = t;
}
inline void gn(unsigned long long &x) {
  long long t;
  gn(t);
  x = t;
}
inline void gn(double &x) {
  double t;
  scanf("%lf", &t);
  x = t;
}
inline void gn(long double &x) {
  double t;
  scanf("%lf", &t);
  x = t;
}
inline void gs(char *s) { scanf("%s", s); }
inline void gc(char &c) {
  while ((c = getchar()) > 126 || c < 33)
    ;
}
inline void pc(char c) { putchar(c); }
inline long long sqr(long long a) { return a * a; }
inline double sqrf(double a) { return a * a; }
const int inf = 0x3f3f3f3f;
const double pi = 3.14159265358979323846264338327950288L;
const double eps = 1e-6;
const int hashtable_mod = 8000019;
const int hashtable_maxn = 10033333;
struct hashtable {
  int head[hashtable_mod];
  long long s[hashtable_maxn];
  int v[hashtable_maxn], zerovalue;
  int next[hashtable_maxn];
  int label[hashtable_mod];
  int tot;
  int tms;
  int &operator[](long long S) {
    int la = abs(S) % hashtable_mod;
    if (label[la] == tms)
      for (int st = head[la]; st; st = next[st])
        if (s[st] == S) return v[st];
    ++tot;
    v[tot] = zerovalue;
    s[tot] = S;
    next[tot] = label[la] == tms ? head[la] : 0;
    head[la] = tot;
    label[la] = tms;
    return v[tot];
  }
  void clear() {
    tms++;
    tot = 0;
  }
} ha;
int n;
int a[4444];
int sua[4444];
int dfs(int l, int r, int k, int op) {
  if (n - l - r < k) return 0;
  if (n - l - r == k) return sua[l + k] - sua[l];
  long long s = (l + 1) * 3 * 5555ll * 5555ll + (r + 1) * 3 * 5555ll +
                (k + 1) * 3ll + (op + 1);
  if (ha[s] & 1) {
    return (ha[s] - 1) / 2;
  } else {
    int ans;
    if (op == 0) {
      ans = max(sua[l + k] - sua[l] - dfs(l + k, r, k, 1),
                sua[l + k + 1] - sua[l] - dfs(l + k + 1, r, k + 1, 1));
    } else {
      ans = max(sua[n - r] - sua[n - r - k] - dfs(l, r + k, k, 0),
                sua[n - r] - sua[n - r - k - 1] - dfs(l, r + k + 1, k + 1, 0));
    }
    ha[s] = 2 * ans + 1;
    return ans;
  }
}
int main() {
  gn(n);
  for (int i = (1), _ed = (n + 1); i < _ed; i++) {
    gn(a[i]);
  }
  for (int i = (1), _ed = (n + 1); i < _ed; i++) sua[i] = sua[i - 1] + a[i];
  ha.clear();
  printf("%d\n", dfs(0, 0, 1, 0));
  return 0;
}
