#include <bits/stdc++.h>
using namespace std;
#define dbg(x) cerr << #x << ": " << x << endl;
const int MAX_N = 20;
const int MAX_MASK = 1 << MAX_N;
int dp[MAX_MASK][MAX_N];
const int INF = 1e9;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<int> a(n);
vector<int> pos(n);
for (int i = 0; i < n; ++i) {
cin >> a[i];
--a[i];
pos[a[i]] = i;
}
for (int mask = 1; mask < (1 << n); ++mask) {
for (int i = 0; i < n; ++i) {
if (!(mask & (1 << i))) continue;
int cnt = __builtin_popcount(mask);
if (cnt == 1) {
dp[mask][i] = pos[i];
break;
}
int cnt_less = 0;
for (int j = 0; j < n; ++j) {
if ((mask & (1 << j)) && (pos[j] > pos[i])) {
++cnt_less;
}
}
int swaps_n = abs((cnt - 1) - (pos[i] + cnt_less));
dp[mask][i] = INF;
for (int j = 0; j < i + 2; ++j) {
if (i == j) continue;
if (!(mask & (1 << j))) continue;
dp[mask][i] = min(dp[mask][i], dp[mask ^ (1 << i)][j] + swaps_n);
}
}
}
int ans = INF;
for (int i = 0; i < n; ++i) {
ans = min(ans, dp[(1 << n) - 1][i]);
}
cout << ans << '\n';
return 0;
}
