#include <bits/stdc++.h>

 using namespace std;

 int a[];

 int dp[][];

 int sum[];

 int main()

 {

     int n;

     scanf("%d", &n);

     for (int i = ; i <= n; i++)

         scanf("%d", a + i), sum[i] = sum[i - ] + a[i];

     int houShouMax = sum[n], xianShouMin = -sum[n];

     for (int i = n - ; i >= ; i--)

     {

         dp[i][] = houShouMax;

         dp[i][] = xianShouMin;

         houShouMax = max(houShouMax, dp[i][] + sum[i]);

         xianShouMin = min(xianShouMin, dp[i][] - sum[i]);

     }

     printf("%d", dp[][]);

     return ;

 }