#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())
#define endl "\n"
template<class T> void chmax(T &a, const T b){ a = max(a, b); }
template<class T> void chmin(T &a, const T b){ a = min(a, b); }
long long gcd(long long a, long long b) { return (a % b) ? gcd(b, a % b) : b; }
long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // ifstream in("input.txt");
    // cin.rdbuf(in.rdbuf());
    ll n;
    cin >> n;
    vector<ll> v(n);
    rep(i, n) cin >> v[i];
    ll ans = LONG_LONG_MAX;
    reps(s, 1, n + 1) {
        if (s % 2 == 0) continue;
        rep(i, n - s + 1) {
            ll mns = 0, pls = 0, tmp = 0;
            rep(j, i) {
                tmp += v[j];
                pls += v[j];
            }
            rep(j, s) {
                ll p = j + 1;
                if (j > (s / 2)) {
                    p = s - j;
                }
                if (v[i + j] > p) {
                    ll rem = v[i + j] - p;
                    tmp += rem;
                    if (mns > 0) {
                        ll cnt = min(mns, rem);
                        mns -= cnt;
                        rem -= cnt;
                    }
                    pls += rem;
                }
                else if (v[i + j] < p) {
                    ll rem = p - v[i + j];
                    if (pls > 0) {
                        ll cnt = min(pls, rem);
                        pls -= cnt;
                        rem -= cnt;
                    }
                    mns += rem;
                }
            }
            reps(j, i + s, n) {
                tmp += v[j];
                pls += v[j];
            }
            if (mns <= pls) {
                chmin(ans, tmp);
            }
        }
    }
    cout << ans << endl;
    return 0;
}