Taro and Jiro will play the following game against each other.

Initially, they are given a sequence a = (a_1, a_2, \ldots, a_N). Until a becomes empty, the two players perform the following operation alternately, starting from Taro:

* Remove the element at the beginning or the end of a. The player earns x points, where x is the removed element.



Let X and Y be Taro's and Jiro's total score at the end of the game, respectively. Taro tries to maximize X - Y, while Jiro tries to minimize X - Y.

Assuming that the two players play optimally, find the resulting value of X - Y.

Constraints

* All values in input are integers.
* 1 \leq N \leq 3000
* 1 \leq a_i \leq 10^9

Input

Input is given from Standard Input in the following format:


N
a_1 a_2 \ldots a_N


Output

Print the resulting value of X - Y, assuming that the two players play optimally.

Examples

Input

4
10 80 90 30


Output

10


Input

3
10 100 10


Output

-80


Input

1
10


Output

10


Input

10
1000000000 1 1000000000 1 1000000000 1 1000000000 1 1000000000 1


Output

4999999995


Input

6
4 2 9 7 1 5


Output

2
n=int(input())
a=list(map(int,input().split()))
dp=[[0]*n for _ in range(n)]
# dp[i][j]:i<=j,i番目からj番目までの数列(j-i+1個)を前にした時、ゲーム終了までに自分が取れる最大得点。i,j=0,..,n-1
sa=[0]
s=0
for ai in a:
      s+=ai
      sa.append(s)
for len in range(1,n+1):
      for l in range(n-len+1):
            r=l+len-1
            s=sa[r+1]-sa[l]
            dp[l][r]=max(s-dp[l][r-1],s-dp[l+1][r] if l+1<n else 0)
print(2*dp[0][-1]-sa[-1])
