#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
#define INF INT_MAX
#define MOD 1000000007
#define all(x) x.begin(), x.end()
template<class T, void UPDATE(T&, T), T MERGE(T, T)>
struct SEGMENT_TREE {
int range_l, range_r;
vector<T> V, lazy; T DEF;
SEGMENT_TREE(int l, int r, T def = T{}){
DEF = def;
V.resize(4*(r-l+1), DEF);
lazy.resize(4*(r-l+1), DEF);
range_l = l, range_r = r;
}
void lazyUpdate(int n, int l, int r){
if(lazy[n] == DEF) return;
UPDATE(V[n], lazy[n]);
if(l < r){
UPDATE(lazy[2*n], lazy[n]);
UPDATE(lazy[2*n+1], lazy[n]);
}
lazy[n] = DEF;
}
void update(int n, int l, int r, int L, int R, T val){
lazyUpdate(n, l, r);
if(r < L or R < l) return;
if(L <= l and r <= R){
UPDATE(lazy[n], val);
lazyUpdate(n, l, r);
return;
}
int m = (l+r)/2;
update(n*2, l, m, L, R, val);
update(n*2+1, m+1, r, L, R, val);
V[n] = MERGE(V[n*2], V[n*2+1]);
}
T query(int n, int l, int r, int L, int R){
lazyUpdate(n, l, r);
if(r < L or R < l) return DEF;
if(L <= l and r <= R) return V[n];
int m = (l+r)/2;
return MERGE(query(n*2, l, m, L, R),
query(n*2+1, m+1, r, L, R));
}
void update(int L, T val){
update(1, range_l, range_r, L, L, val);
}
T query(int L, int R){
if(L <= R) return query(1, range_l, range_r, L, R);
return min(query(1, range_l, range_r, L, range_r),
query(1, range_l, range_r, 0, R));
}
};
void seg_upd(int &a, int b){a = b;}
int seg_merge(int a, int b){return min(a, b);}
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
int N; cin >> N;
vi V(N); for(auto &i : V) cin >> i;
auto bb = [&](int x){
return (x+N)%N;
};
vi sum(N); int sz = (N+1)/2;
sum[sz-1] = accumulate(V.begin(), V.begin()+sz, 0);
for(int x = sz; x != sz-1; x = bb(x+1)){
sum[x] = V[x]+sum[bb(x-1)]-V[bb(x-sz)];
}
SEGMENT_TREE<int, seg_upd, seg_merge> ST(0, N-1, INF);
for(int x = 0; x < N; x++) ST.update(x, sum[x]);
int ans = 0;
for(int x = 0; x < N; x++)
ans = max(ans, ST.query(x, bb(x+sz-1)));
cout << ans << endl;
return 0;
}
