#include <bits/stdc++.h> 
 
using namespace std;  
 
typedef long long ll;  
typedef pair<int, int> ii;  
 
const int INF = 1e9;  
const ll LINF = 1e18;  
 
const int N = 5e3 + 5; 
 
int n;  
int a[N]; 
 
ll dp[N][N]; // dp[l][r] = Chênh lệch điểm số tối đa mà người đi trước có thể đạt được khi chơi trên đoạn [l, r]
 
int main() {
	ios::sync_with_stdio(false); 
	cin.tie(nullptr); 	
	cin >> n; 
	for (int i = 1; i <= n; i++) cin >> a[i]; 
 
	for (int l = n; l >= 1; l--) {
		for (int r = l; r <= n; r++) {
			if (l == r) {
				dp[l][r] = a[l]; 
				continue; 
			}
			dp[l][r] = max(a[l] - dp[l + 1][r], a[r] - dp[l][r - 1]);
		}
	}
 
	ll tot = 0;  
	for (int i = 1; i <= n; i++) tot += a[i]; 
 
	// Có p1 + p2 = tot
	// và p1 - p2 = dp[1][n]
	// =>  2 * p1 = tot + dp[1][n]
	ll p1 = (tot + dp[1][n]) / 2; // Điểm số của người chơi thứ nhất
 
	cout << p1 << '\n'; 
}

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