#include<bits/stdc++.h>
#include<unordered_map>
using namespace std;
typedef unsigned long long ll;
typedef double D;
const ll inf=(1ll<<61);
const ll mod=1e9+7;
const int MX=5e5+9;
int n,a[MX],sums[MX],k;
ll b[MX];
ll seg[MX*6];
void build(int node,int l,int r){
if(l==r){
seg[node]=b[l];
return;
}
int mid=(l+r)/2;
build(node*2,l,mid);
build(node*2+1,mid+1,r);
seg[node]=min(seg[node*2],seg[node*2+1]);
}
ll q(int node,int l,int r,int s,int e){
if(l>e||r<s)return inf;
if(l>=s&&r<=e)return seg[node];
int mid=(l+r)/2;
return min(q(node*2,l,mid,s,e),q(node*2+1,mid+1,r,s,e));
}
int main(){
cin>>n;
k=(n/2)+(n%2);
for(int i=0;i<n;i++){
scanf("%d",&a[i]);
sums[i]=a[i];
if(i)sums[i]+=sums[i-1];
}
for(int i=0;i<n;i++){
if(i+k-1<n){
b[i]=sums[i+k-1];
if(i)b[i]-=sums[i-1];
continue;
}
b[i]=sums[n-1]-sums[i-1];
int x=k-(n-i);
b[i]+=sums[x-1];
}
build(1,0,n-1);
ll ans=0;
for(int i=0;i<n;i++){
ll mn=inf;
if(i-k+1>=0){
mn=q(1,0,n-1,i-k+1,i);
}
else {
mn=q(1,0,n-1,0,i);
int x=i+1;
x=k-x;
mn=min(mn,q(1,0,n-1,n-x,n-1));
}
ans=max(ans,mn);
}
cout<<ans<<endl;
}
