#include <bits/stdc++.h>   using namespace std;   void ga(int N, int *A) {     for (int i(0); i < N; i++) scanf( %d , A + i);   }   unordered_map<int, int> dp;   int N, S[(4000)];   int dyn(int a, int b, int K, bool x) {     if (b - a + 1 < K) return 0;     if (b - a + 1 == K) return (S[b] - (a ? S[a - 1] : 0));     if (dp.count(             (a + (4000) * b + (4000) * (4000) * K + x * (4000) * (4000) * 100)))       return dp[(a + (4000) * b + (4000) * (4000) * K +                  x * (4000) * (4000) * 100)];     if (!x)       return dp[(a + (4000) * b + (4000) * (4000) * K +                  x * (4000) * (4000) * 100)] =                  max(-dyn(a + K, b, K, 1) + (S[a + K - 1] - (a ? S[a - 1] : 0)),                      -dyn(a + K + 1, b, K + 1, 1) +                          (S[a + K] - (a ? S[a - 1] : 0)));     return dp[(a + (4000) * b + (4000) * (4000) * K +                x * (4000) * (4000) * 100)] =                max(-dyn(a, b - K, K, 0) +                        (S[b] - (b - K + 1 ? S[b - K + 1 - 1] : 0)),                    -dyn(a, b - K - 1, K + 1, 0) +                        (S[b] - (b - K ? S[b - K - 1] : 0)));   }   int main(void) {     dp.max_load_factor(.4);     scanf( %d , &N), ga(N, S);     for (int k(1); k < N; k++) S[k] += S[k - 1];     printf( %d n , dyn(0, N - 1, 1, 0));     return 0;   }   