#include <bits/stdc++.h>
using namespace std;
#define FOR(i, l, r) for(int i = (l); i < (r); ++i)
#define ROF(i, r, l) for(int i = (r) - 1; i >= (l); --i)
#define mp make_pair
#define mt make_tuple
#define ff first
#define ss second
#define all(v) begin(v), end(v)
#define rall(v) rbegin(v), rend(v)
#define pb push_back
#define eb emplace_back
#define sz(v) (int)v.size()
#define sum_of(v) accumulate(all(v), 0ll)
#define compact(v) v.erase(unique(all(v)), end(v))
#define dbg(x) "[" #x " = " << (x) << "]"
template<typename T>
bool minimize(T& a, const T& b){
if(a > b) return a = b, true;
return false;
}
template<typename T>
bool maximize(T& a, const T& b){
if(a < b) return a = b, true;
return false;
}
using ll = long long;
using db = double;
using ld = long double;
using ull = unsigned long long;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
using vi = vector<int>;
using vb = vector<bool>;
using vc = vector<char>;
using vl = vector<ll>;
using vd = vector<db>;
using vpi = vector<pi>;
using vpl = vector<pl>;
void setIO(){
ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef LOCAL
freopen("task.inp", "r", stdin);
freopen("task.out", "w", stdout);
#endif // LOCAL
}
const int MAX = 5e5 + 5;
int N;
ll a[MAX * 2], b[MAX];
ll spt[20][MAX];
ll query_manual(int l, int r){
if(l > r) return 0;
return a[r] - a[l-1];
}
ll query_cyclic(int l, int r){
if(l <= r) return query_manual(l, r);
return query_manual(l, N) + query_manual(1, r);
}
ll query_max_manual(int l, int r){
int k = 31 - __builtin_clz(r - l + 1);
return max(spt[k][l], spt[k][r - (1 << k) + 1]);
}
ll query_max_cyclic(int l, int r){
if(l <= r) return query_max_manual(l, r);
return max(query_max_manual(l, N), query_max_manual(1, r));
}
signed main(){
setIO();
cin >> N;
FOR(i, 1, N+1){
cin >> a[i];
a[i] += a[i-1];
}
if(N == 2){
cout << *max_element(a+1, a+1+N) << '\n';
return 0;
}
int len = (N/2);
for(int i = 1, j = len; i <= N; ++i){
spt[0][i] = query_cyclic(i, j);
if(j == N) j = 1;
else ++j;
}
for(int i = 1; (1 << i) <= N; ++i){
for(int j = 1; j + (1 << i) - 1 <= N; ++j){
spt[i][j] = max(spt[i-1][j], spt[i-1][j+(1<<(i-1))]);
}
}
ll ans = -1e18;
FOR(i, 1, N+1){
int l = (i == N ? 1 : i+1), r = (i > len ? i - len : i - len + N);
// cout << dbg(l) << dbg(r) << dbg(query_max_cyclic(l, r)) << '\n';
maximize(ans, a[N] - query_max_cyclic(l, r));
}
cout << ans << '\n';
return 0;
}
