#include <fstream>
#include <climits>
#include <vector>
#include <cassert>
#include <algorithm>
#define ll long long
using namespace std;

const int NMAX = 1e5;

int a[NMAX + 1];

pair <int, pair <int, int> > s[NMAX + 1];

bool viz[NMAX + 1];

int n;

int nxt(int val)
{
    if (val == n)
        return 1;
    return val + 1;
}

int prv(int val)
{
    if (val == 1)
        return n;
    return val - 1;
}

signed main()
{
    ifstream cin("oo.in");
    ofstream cout("oo.out");
    int i;
    cin >> n;
    for (i = 1; i <= n; i++)
        cin >> a[i];
    for (i = 1; i < n; i++)
        s[i] = {a[i] + a[i + 1], {i, i + 1}};
    s[n] = {a[n] + a[1], {1, n}};
    sort(s + 1, s + n + 1, greater <pair <int, pair <int, int> > > ());
    int ans = 0;
    for (i = 1; i <= n; i++)
        if (!viz[s[i].second.first] and !viz[s[i].second.second])
        {
            ans += s[i].first;
            viz[s[i].second.first] = 1;
            viz[s[i].second.second] = 1;
            viz[prv(s[i].second.first)] = 1;
            viz[nxt(s[i].second.second)] = 1;
        }
    cout << ans;
}