#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
int fx[] = {+0, +1, +0, -1, +1, +1, -1, -1, +0};
int fy[] = {+1, +0, -1, +0, +1, -1, +1, -1, +0};
template <typename T>
inline T GCD(T a, T b) {
  a = abs(a);
  b = abs(b);
  if (a < b) swap(a, b);
  while (b) {
    a = a % b;
    swap(a, b);
  }
  return a;
}
template <typename T>
inline T EGCD(T a, T b, T &x, T &y) {
  if (a == 0) {
    x = 0;
    y = 1;
    return b;
  }
  T x1, y1;
  T d = EGCD(b % a, a, x1, y1);
  x = y1 - (b / a) * x1;
  y = x1;
  return d;
}
template <typename T>
inline T LCM(T x, T y) {
  T tp = GCD(x, y);
  if ((x / tp) * 1. * y > 9e18) return 9e18;
  return (x / tp) * y;
}
template <typename T>
inline T BigMod(T A, T B, T M = MOD) {
  T ret = 1;
  while (B) {
    if (B & 1) ret = (ret * A) % M;
    A = (A * A) % M;
    B = B >> 1;
  }
  return ret;
}
template <typename T>
inline T InvMod(T A, T M = MOD) {
  return BigMod(A, M - 2, M);
}
template <typename T>
T scani(T &n) {
  n = 0;
  bool negative = false;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') negative = true;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    n = n * 10 + c - 48;
    c = getchar();
  }
  if (negative) n = ~(n - 1);
  return n;
}
template <typename T>
void write(T n, int type = true) {
  if (n < 0) {
    putchar('-');
    n = -n;
  }
  if (!n) {
    putchar('0');
    if (type == 32)
      putchar(' ');
    else if (type)
      putchar('\n');
    return;
  }
  char buff[22];
  int len = 0;
  while (n) buff[len++] = n % 10 + 48, n /= 10;
  for (int i = len - 1; i >= 0; i--) putchar(buff[i]);
  if (type == 32)
    putchar(' ');
  else if (type)
    putchar('\n');
}
int scans(char *a) {
  int i = 0;
  char c = 0;
  while (c < 33) c = getchar();
  while (c > 33) {
    a[i++] = c;
    c = getchar();
  }
  a[i] = 0;
  return i;
}
const int N = 4005 + 200;
int dp[N >> 1][181][90][2];
int in[N];
int n;
int ans_me(int L, int df, int k, int tern) {
  int &ret = dp[L][df + 90][k][tern];
  if (ret != -1) return ret;
  int remSiz = (n - 2 * (L - 1) + df);
  int R = n - (L - 1) + df;
  if (remSiz < k) return 0;
  if (tern) {
    ret = ans_me(L + k, df + k, k, tern ^ 1) + (in[L + k - 1] - in[L - 1]);
    if (remSiz >= k + 1)
      ret = max(ret, ans_me(L + k + 1, df + k + 1, k + 1, tern ^ 1) +
                         (in[L + k] - in[L - 1]));
  } else {
    ret = ans_me(L, df - k, k, tern ^ 1) - (in[R] - in[R - k]);
    if (remSiz >= k + 1)
      ret = min(ret, ans_me(L, df - k - 1, k + 1, tern ^ 1) -
                         (in[R] - in[R - k - 1]));
  }
  return ret;
}
int main() {
  memset(dp, -1, sizeof(dp));
  scani(n);
  for (int i = 1; i <= n; i++) scani(in[i]);
  for (int i = 1; i <= n; i++) in[i] += in[i - 1];
  int ans = ans_me(1, 0, 1, 1);
  write(ans);
  return 0;
}
