#include <bits/stdc++.h>
using namespace std;
#define FINISH cerr << "FINISH" << endl;
#define debug(x) cerr << #x << " == " << x << endl
#define el '\n'
#define fir first
#define sec second
typedef long long ll;
typedef pair<int, int> PII;
const int mod = 1000000007;
const int inf = 0x3f3f3f3f;
const int N = 400020;
int t[N], n, tot;
int lowbit(int x)
{
	return x & (-x);
}
void add(int x, int val)
{
	while (x <= n) {
		t[x] += val;
		x += lowbit(x);
	}
}
int getsum(int x)
{
	int rr = 0;
	while (x >= 1) {
		rr += t[x];
		x -= lowbit(x);
	}
	return rr;
}
ll calc(vector<int>& a)
{
	for (int i = 0; i <= n; i++)
		t[i] = 0;
	ll sum = 0;
	for (int i = 1; i <= n; i++) {
		add(a[i] + 1, 1);
		sum += getsum(a[i]);
	}
	return n * (n - 1) / 2 - sum;
}
void getans(int now, vector<int>& a)
{
	if (now == 0)
		return;
	vector<int> b = a;
	for (int i = 1; i <= n; i++) {
		b[i] ^= now;
	}
	ll sum1 = calc(a);
	ll sum2 = calc(b);
	/*debug(now);
	for (int i = 1; i <= n; i++) {
		cout << a[i] << " ";
	}
	cout << endl;
	for (int i = 1; i <= n; i++) {
		cout << b[i] << " ";
	}
	cout << endl;
	cout << sum1 << " " << sum2 << endl;*/
	if (sum1 > sum2 + 1) {
		a = b;
	}
	getans(now / 2, a);
}
void solve()
{
	cin >> n;
	vector<int> a(n + 1);
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	ll ans = calc(a);
	getans(n / 2, a);
	ans = min(ans, calc(a) + 1);
	cout << ans << endl;
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int T = 1;
	// cin >> T;
	while (T--) {
		solve();
	}
	return 0;
}