#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:x) cout << it << " "; cout << #y << endl;
typedef pair<int,int>pii;
typedef pair<pii,pii>pi2;
void solve(){
int n;
cin >> n;
int arr[2*n+1];
for(int x=1;x<=n;x++){
cin >> arr[x];
arr[x+n]=arr[x];
}
int prefix[2*n+1];
memset(prefix,0,sizeof(prefix));
for(int x=1;x<=2*n;x++){
prefix[x]=prefix[x-1]+arr[x];
}
int k=(n+1)/2;
int ptr=k;
deque<pii>d;
int best=0;
int mini[n];
for(int x=0;x<n;x++) mini[x]=1e17;
for(int x=1;x<=2*n;x++){
while(ptr<=2*n&&ptr<=x+k-1){
while(!d.empty()&&d.back().first>=prefix[ptr]-prefix[ptr-k]){
d.pop_back();
}
d.push_back({prefix[ptr]-prefix[ptr-k],ptr});
ptr++;
}
while(!d.empty()&&d.front().second<x) d.pop_front();
if(!d.empty())mini[x%n]=min(mini[x%n],d.front().first);
}
for(int x=0;x<n;x++) best=max(best,mini[x]);
cout << best;
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
//freopen("in.txt", "r", stdin);
int t=1;
//cin >> t;
while(t--){
solve();
}
}
