#include <stdio.h>

#define MAX_N (11234)

#define max(x,y) (x >= y ? x : y)
#define min(x,y) (x <= y ? x : y)

int t[MAX_N], N;

long long int mem[2][MAX_N];

int main(int argc, char *noargs[]) {
  int i, r, k, j, pr;
  for(;;) {
    if (scanf("%d", &N) == EOF) break;
    for (i = 0; i < N; ++i) {
      scanf("%d", &t[i]);
    }
    r = 0;
    for (i = 0; i < N-1; ++i) {
      mem[r][i] = max(t[i], t[i+1]);
    }
    for (k = 4; k <= N; k += 2) {
      pr = r; 
      r = 1 - r;
      for (i = 0; i <= N-k; ++i) {
	long long int pi, pj;
	j = i+k-1;
	pi = t[i] + min(mem[pr][i+1], mem[pr][i+2]);
	pj = t[j] + min(mem[pr][i], mem[pr][i+1]);
	mem[r][i] = max(pi, pj);
      }
    }
    printf("%lld\n", mem[r][0]);
  }
  return 0;
}