#include <bits/stdc++.h>
#define int long long
#define pii pair<int, int>
#define fi first
#define se second
#define vi vector <int>
#define pq priority_queue
#define MASK(i) (1ll<<(i))
#define BIT(x, i) (((x) >> (i)) & 1)
#define x0 ___x0
#define y0 ___y0
#define div ___div
#define next ___next
#define prev ___prev
#define left ___left
#define right ___right
#define pos pisosi
#define pb push_back
#define pf push_front
using namespace std;
//const int mod = ;
//void add (int &a, const int&b){
// a+=b;
// if (a>=mod) a-=mod;
//}
//
//void sub (int&a, const int&b){
// a-=b;
// if (a<0) a+=mod;
//}
//
//void mul (int&a, const int&b){
// a*=b;
// a%=mod;
//}
template<class X, class Y>
bool minimize(X &x, const Y&y){
if (x<=y) return false;
else{
x = y;
return true;
}
}
template<class X, class Y>
bool maximize (X &x, const Y&y){
if (x>=y) return false;
else{
x = y;
return true;
}
}
/////////////////////////////////////////////////////////////////////////////////
//// dang nhap ham
//#ifndef davele
//
//#endif // davele
//
//// chay thu ham main:
//
//#ifdef davele
//
//#endif // davele
////////////////////////////////////////////////////////////////////////////
//const int lim = , limit = , inf = ;
const string name = "chonso";
const int lim = 5e5, limit = lim+5;
int n, k;
int rmq[limit][21];
int sum[limit], A[limit], sr[limit];
int next (int id, int step){
return (id+step)%n;
}
int prev (int id, int step){
return (id-step+n)%n;
}
int getmax (int l, int r){
int tm = 31-__builtin_clz (r-l+1);
return max (rmq[l][tm], rmq[r-MASK(tm)+1][tm]);
}
int get (int st, int en){
int furthest = prev (en, k-1);
if (furthest<=en){
if (st<=furthest) return getmax (st,furthest);
else return max(getmax(st, n-1), getmax(0, furthest));
}
else{
if (st<=furthest) return getmax (st, furthest);
}
}
namespace sub3{
void process(){
sum[0] = A[0];
for (int i=1; i<n; i++) sum[i] = sum[i-1] + A[i];
//
k = n/2;
for (int i=0; i<n; i++){
// sr[i] = i -> next (i, k-1)
if (next(i, k-1)>=i){
sr[i] = sum[next(i, k-1)] - (i==0 ? 0 : sum[i-1]);
}
else{
sr[i] = sum[n-1] - sum[i-1] + sum[next(i, k-1)];
}
}
//
for (int i=0; i<n; i++) rmq[i][0] = sr[i];
//
for (int i=1; i<=20; i++) for (int j=0; j+MASK(i)-1<n; j++){
rmq[j][i] = max (rmq[j][i-1], rmq[j+MASK(i-1)][i-1]);
}
//
int ret = 0;
for (int i = 0; i<n; i++){
int st = next(i, 1);
int en = prev (i, 1);
// lay trong doan [st; en]
int comp = get (st, en);
maximize (ret, sum[n-1]-comp);
}
cout<<ret;
}
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
//
if (fopen((name+".inp").c_str(), "r")){
freopen ((name+".inp").c_str(), "r", stdin);
freopen ((name+".out").c_str(), "w", stdout);
}
//
cin>>n;
for (int i=0; i<n; i++) cin>>A[i];
//
sub3::process();
}
