//Dost SEFEROĞLU
#include <bits/stdc++.h>
#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")
using namespace std;
#define int long long
#define pii pair<int,int>
#define ff first
#define ss second
#define sp << " " <<
#define all(cont) cont.begin(),cont.end()
#define vi vector<int>
const int inf = 2e18,MOD = 998244353,N = 2e5+1;
int add(int x,int y){
return ((x+y) >= MOD ? x+y-MOD : x+y);
}
int mult(int x,int y) {
return ((x*y)%MOD);
}
struct Q {
stack<pii> s1,s2;
void push(int op) {
if (!s1.empty()) s1.push({op,min(s1.top().ss,op)});
else s1.push({op,op});
}
void pop() {
if (s2.empty()) {
int cur = inf;
while (!s1.empty()) {
cur = min(s1.top().ff,cur);
s2.push({s1.top().ff,cur});
s1.pop();
}
}
s2.pop();
}
int mn() {
int pp;
if (!s1.empty() && !s2.empty()) pp = min(s2.top().ss,s1.top().ss);
else if (!s1.empty()) pp = s1.top().ss;
else if (!s2.empty()) pp = s2.top().ss;
else pp = inf;
return pp;
}
};
void solve() {
int n;
cin >> n;
int ans = 0;
vi a(n+1),p(n+1,0);
for (int i=1;i<=n;i++) cin >> a[i];
for (int i=1;i<=n;i++) p[i] = p[i-1]+a[i];
//i...i-t+1 sliding min
auto ask = [&](int l,int r) -> int {
if (l <= r) return p[r]-p[l-1];
return p[n]-p[l-1]+p[r];
};
vi f(n+1,0);
int t = (n+1)/2;
for (int i=1;i<=n;i++) {
f[i] = ask(i,((i+t-1) > n ? (i+t-1)-n : (i+t-1)));
}
Q queue;
for (int i=1;i<=t;i++) queue.push(f[i]);
for (int i=t;i<=n+t-1;i++) {
/* cout << i sp queue.mn() << '\n'; */
ans = max(ans,queue.mn());
queue.pop();
queue.push(f[i%n+1]);
}
cout << ans << '\n';
}
int32_t main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#ifdef Dodi
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);/*
#else
freopen("fcolor.in","r",stdin);
freopen("fcolor.out","w",stdout); */
#endif
int t = 1;
//cin >> t;
while (t --> 0) solve();
}
