#include <cstdio>
#include <stdio.h>
#include <stdbool.h>
#include <iostream>
#include <map>
#include <vector>
#include <climits>
#include <stack>
#include <string>
#include <queue>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cmath>
#include <cctype>
#include <bitset>
#include <iomanip>
#include <cstring>
#include <numeric>
#include <cassert>
using namespace std;
#define int long long
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define fi first
#define se second
int32_t main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, ans=0;
cin>>n;
vector<int> psum(2*n+1, 0);
for (int i=1; i<=n; ++i)cin>>psum[i], psum[i+n]=psum[i];
for (int i=1; i<=2*n; ++i)psum[i]+=psum[i-1];
multiset<int> s;
for (int i=1; i+(n+1)/2-1<=2*n; ++i){
s.insert(psum[i+(n+1)/2-1]-psum[i-1]);
if (i>=(n+1)/2)ans=max(ans, *s.begin()), s.erase(s.lower_bound(psum[i]-psum[i-(n+1)/2]));
}
cout<<ans;
}
