include <bits/stdc++.h>

using namespace std; using ll = long long;

define fi first

define se second

int N; ll ans = 0;

void solve(auto& a, int j) { ll psum = 0, nsum = 0; for (int i = j; i < N; i += 2) psum += (N - i) a[i]; for (int i = j + 1; i < N; i += 2) nsum += (N - i) a[i];

ans = max(ans, psum - nsum);
for (int i = 0; i < N; i += 2)
{
    psum = psum * 2 - a[i] * 2;

    if (N % 2 == 0) psum -= (N - 2) * a[i];
    else psum = psum - N * a[i] + a[(i + 1) % N];

    nsum = nsum * 2 - a[(i + 1) % N] * 2;

    if (N % 2 == 0) nsum -= (N - 2) * a[(i + 1) % N];
    else nsum = nsum - (N - 1) * a[(i + 1) % N] + 2 * a[i];

    ans = max(ans, psum - nsum);
}

}

int main() { cin >> N;

vector<int> a(N);
for (int& i : a) cin >> i;

solve(a, 0);
solve(a, 1);

cout << ans << endl;

}