#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define pb push_back
#define vll vector<ll>
#define pll pair<ll, ll>
typedef long long ll;
const ll inf=1e17;
void solve(){
ll n;
cin>>n;
vll a(2*n);
for(ll i=0;i<n;i++){
cin>>a[i];
a[i+n]=a[i];
}
vll val(2*n, inf);
ll pre=0;
ll siz=n/2;
if(n%2==1) siz++;
for(ll i=0;i<siz;i++){
pre+=a[i];
}
val[0]=pre;
ll p1=0;
ll p2=siz;
for(ll i=1;i<n;i++){
pre-=a[p1];
pre+=a[p2];
p1++;
p2++;
val[i]=pre;
}
vll ans(n, inf);
p1=0;
p2=1;
multiset<ll> st;
st.insert(val[0]);
for(ll i=0;i<2*n;i++){
while(p1<i-siz+1){
st.erase(st.find(val[p1]));
p1++;
}
while(p2<=i){
st.insert(val[p2]);
p2++;
}
ans[i%n]=min(ans[i%n], *st.begin());
}
ll o=0;
for(ll i=0;i<n;i++){
o=max(o, ans[i]);
}
cout<<o<<'\n';
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
solve();
return 0;
}
