#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define int long long
#define x first
#define y second

using namespace std;
using namespace __gnu_cxx;
using namespace __gnu_pbds;

typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> set_t;

int f(vector<int>& a) {
    int res = 0, n = a.size();
    set_t s;
    for (int i = 0; i < n; ++i) {
        res += s.size() - s.order_of_key(a[i]);
        s.insert(a[i]);
    }
    return res;
}

signed main() {
    cin.tie(0);
    cout.tie(0);
    ios_base::sync_with_stdio(0);

    int n;
    cin >> n;
    vector<int> a(n);
    for (auto &i : a) {
        cin >> i;
    }
    int curr_res = f(a), was = 0;
    for (int q = 1; q < n; q += q) {
        vector<int> b = a;
        vector<int> pos(n);
        for (int i = 0; i < n; ++i) {
            pos[a[i]] = i;
        }
        for (int i = 0; i < n; ++i) {
            if (i < (i ^ q)) {
                swap(b[pos[i]], b[pos[i ^ q]]);
            }
        }

        int res = f(b);
        if (res < curr_res) {
            curr_res = res;
            a = b;
            was = 1;
        }
    }

    cout << curr_res + was;
    return 0;
}