#include <bits/stdc++.h>
using namespace std;
const int len = 5e5+5, inf = 1e9;
int arr[len], out[len], val[4*len], n;
void build(int p, int l, int r){
val[p] = inf;
if (l == r)
return;
int mid = (l+r)/2;
build(2*p, l, mid);
build(2*p+1, mid+1, r);
}
void prop(int p, int l, int r){
if (val[p] == inf || l == r)
return;
val[2*p] = min(val[2*p], val[p]);
val[2*p+1] = min(val[2*p+1], val[p]);
val[p] = inf;
}
void upd(int p, int l, int r, int i, int j, int v){
prop(p, l, r);
if (r < i || j < l)
return;
if (i <= l && r <= j)
return void(val[p] = min(val[p], v));
int mid = (l+r)/2;
upd(2*p, l, mid, i, j, v);
upd(2*p+1, mid+1, r, i, j, v);
}
int ask(int p, int l, int r){
prop(p, l, r);
if (l == r)
return val[p];
int mid = (l+r)/2;
return max(ask(2*p, l, mid), ask(2*p+1, mid+1, r));
}
void change(int i, int j, int v){
if (i <= j){
upd(1, 0, n-1, i, j, v);
}
else{
upd(1, 0, n-1, i, n-1, v);
upd(1, 0, n-1, 0, j, v);
}
}
int main(){
scanf("%d", &n);
for (int i = 0; i < n; i++)
scanf("%d", &arr[i]);
build(1, 0, n-1);
int k = (n+1)/2;
for (int i = 0, j = 0, sum = 0; i < n; i++){
while ((n+j-i)%n < k){
sum += arr[j];
j = (j+1)%n;
}
change(i, (j+n-1)%n, sum);
sum -= arr[i];
}
printf("%d\n", ask(1, 0, n-1));
return 0;
}
