#include <iostream>
#include <cmath>
#include <unordered_map>
#include <map>
#include <set>
#include <queue>
#include <vector>
#include <string>
#include <iomanip>
#include <algorithm>
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
using namespace std;
typedef long long ll;
ll linf = 1e15+1;
inline void scoobydoobydoo(){
ios::sync_with_stdio(false);
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
}
int segmet[(int)1e8];
int main(){
scoobydoobydoo();
int n; cin >> n;
vector<int> v(n);
for (int i = 0; i < n; i++)cin >> v[i];
int half = ceil((double)n/2.0);
int startSum = 0;
for (int i = 0; i < half; i++){
startSum += v[i];
}
int i = 0, j = half-1;
segmet[i] = startSum;
while (i < n){
j = (j+1)%n;
startSum += v[j];
startSum -= v[i++];
segmet[i] = startSum;
}
multiset<int> ms;
for (int i = 0; i < half; i++){
ms.insert(segmet[i]);
}
int maxi = -1;
i = 0; j = half-1;
while (i < n){
maxi = max(maxi, *ms.begin());
auto it = ms.find(segmet[i]);
ms.erase(it);
i++;
j = (j+1)%n;
ms.insert(segmet[j]);
}
cout << maxi << endl;
return 0;
}
