#include <bits/stdc++.h>
using namespace std;
const int MOD = (int)1e9 + 7;
const int INF = (int)1e9;
const long long LINF = (long long)1e18;
const long double PI = acos((long double)-1);
const long double EPS = 1e-9;
inline long long gcd(long long a, long long b) {
  long long r;
  while (b) {
    r = a % b;
    a = b;
    b = r;
  }
  return a;
}
inline long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
inline long long fpow(long long n, long long k, int p = MOD) {
  long long r = 1;
  for (; k; k >>= 1) {
    if (k & 1) r = r * n % p;
    n = n * n % p;
  }
  return r;
}
template <class T>
inline int chkmin(T& a, const T& val) {
  return val < a ? a = val, 1 : 0;
}
template <class T>
inline int chkmax(T& a, const T& val) {
  return a < val ? a = val, 1 : 0;
}
template <class T>
inline T isqrt(T k) {
  T r = sqrt(k) + 1;
  while (r * r > k) r--;
  return r;
}
template <class T>
inline T icbrt(T k) {
  T r = cbrt(k) + 1;
  while (r * r * r > k) r--;
  return r;
}
inline void addmod(int& a, int val, int p = MOD) {
  if ((a = (a + val)) >= p) a -= p;
}
inline void submod(int& a, int val, int p = MOD) {
  if ((a = (a - val)) < 0) a += p;
}
inline int mult(int a, int b, int p = MOD) { return (long long)a * b % p; }
inline int inv(int a, int p = MOD) { return fpow(a, p - 2, p); }
const int maxn = 200000 + 10;
int n;
int a[maxn];
long long sum[maxn];
long long f[maxn][2];
long long g[maxn];
long long h[maxn];
void solve() {
  cin >> n;
  for (int i = (0); i < (n); i++) cin >> a[i];
  a[1] += a[0], n--;
  for (int i = (0); i < (n); i++) a[i] = a[i + 1];
  for (int i = (0); i < (n); i++) sum[i + 1] = sum[i] + a[i];
  g[n] = -sum[n];
  h[n] = +sum[n];
  for (int i = (n)-1; i >= (0); i--) {
    f[i][1] = g[i + 1] + sum[i];
    f[i][0] = h[i + 1];
    g[i] = min(f[i][0] - sum[i], g[i + 1]);
    h[i] = max(f[i][1], h[i + 1]);
  }
  cout << f[0][0] << "\n";
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  solve();
  return 0;
}
