#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
using std::mt19937_64;
using std::random_device;
using std::uniform_int_distribution;
#include <numeric>
#define ff first
#define ss second
#define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define vi vector<int>
#define mii map<int,int>
#define pqb priority_queue<int>
#define pqs priority_queue<int,vi,greater<int> >
#define setbits(x) __builtin_popcountll(x)
#define zrobits(x) __builtin_ctzll(x)
#define mod 1000000007
#define inf (int) 1e17+1
#define ps(x,y) fixed<<setprecision(y)<<x
#define mk(arr,n,type) type *arr=new type[n];
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef tree<pair<int,int>, null_type, less<pair<int,int>>, rb_tree_tag, tree_order_statistics_node_update> pbds;
void cpc()
{
#ifndef ONLINE_JUDGE
freopen("paintbarn.in", "r", stdin);
freopen("paintbarn.out", "w", stdout);
#endif
}
// int dx[] = {-1, 0, 1, 0};
// int dy[] = {0, 1, 0, -1};
int exp(int x, int n, int m) {
if(x == 0 and n == 0) return 1;
x %= m;
int res = 1;
while (n > 0) {
if (n % 2 == 1) { res = res * x % m; }
x = x * x % m;
n /= 2;
}
return res;
}
int gcd(int a,int b){
if(a == 0) return b;
return gcd(b%a,a);
}
stack<pair<int,int>> s1,s2;
signed main()
{
// cpc();
int t=1;
// cin >> t;
while(t--){
int n;
cin >> n;
vector<int> v(n);
for(auto &x:v) cin >> x;
vector<int> a;
int ct = (n+1)/2-1;
int i = n-ct;
while(ct--){
a.pb(v[i++]);
}
for(int j = 0 ; j < n; j++) a.pb(v[j]);
ct = (n+1)/2-1;
i = 0;
while(ct--){
a.pb(v[i++]);
}
// for(auto &x:a) cout<<x<<" ";
// cout<<endl;
int cur_sum = 0;
ct = (n+1)/2-1;
for(int i = 0 ; i <= ct; i++){
cur_sum += a[i];
}
s1.push({cur_sum,cur_sum});
// cout<<cur_sum<<endl;
for(int i = ct+1; i <=2*ct; i++){
cur_sum -= a[i-ct-1];
cur_sum += a[i];
s1.push({cur_sum,min(s1.top().ss,cur_sum)});
}
// while(!s1.empty()){
// cout<<s1.top().ff<<" "<<s1.top().ss<<endl;
// s1.pop();
// }
// cout<<cur_sum<<endl;
int ans = s1.top().ss;
for(int i = 2*ct+1; i < a.size(); i++){
cur_sum -= a[i-ct-1];
cur_sum += a[i];
// cout<<cur_sum<<endl;
if(s2.empty()){
while(!s1.empty()){
if(s2.empty()) s2.push({s1.top().ff,s1.top().ff});
else s2.push({s1.top().ff,min(s1.top().ff,s2.top().ss)});
s1.pop();
}
}
s2.pop();
if(s1.empty()) s1.push({cur_sum,cur_sum});
else s1.push({cur_sum,min(s1.top().ss,cur_sum)});
int mi = s1.top().ss;
if(!s2.empty()) mi = min(s2.top().ss,s1.top().ss);
ans = max(ans,mi);
}
cout<<ans<<endl;
}
return 0;
}
