#include "bits/stdc++.h"
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
// https://codeforces.com/blog/entry/79148
class Timer: chrono::high_resolution_clock {
const time_point start_time;
public:
Timer(): start_time(now()) {}
rep elapsed_time() const {
return chrono::duration_cast<chrono::milliseconds>(now() - start_time).count();
}
} timer;
struct FenwickTree {
int n;
vector<int> tree;
FenwickTree(int n_) {
n = n_;
tree.resize(n + 1, 0);
}
void update(int p, int k) {
while (p <= n) {
tree[p] += k;
p += p & (-p);
}
}
int prefixQuery(int r) {
int res = 0;
while (r) {
res += tree[r];
r -= r & (-r);
}
return res;
}
int query(int l, int r) {
return prefixQuery(r) - prefixQuery(l - 1);
}
};
int main() {
cin.tie(0);
ios::sync_with_stdio(0);
int n;
cin >> n;
vector<int> pos(n + 1), dp(n + 1, 1e9);
for (int i = 1; i <= n; i++) {
int x;
cin >> x;
pos[x] = i;
}
vector<vector<int>> inv(n + 1, vector<int>(n + 1, 0));
for (int i = 1; i <= n; i++) {
FenwickTree fwt(n);
for (int j = i; j <= n; j++) {
inv[i][j] = inv[i][j - 1] + fwt.query(pos[j], n);
fwt.update(pos[j], 1);
}
}
dp[0] = 0;
for (int i = 1; i <= n; i++) {
FenwickTree fwt(n);
for (int j = i; j <= n; j++) {
fwt.update(pos[j], 1);
}
int cur = 0;
for (int j = i; j <= n; j++) {
cur += fwt.prefixQuery(pos[j]) - 1;
dp[j] = min({dp[j], dp[i - 1] + cur, dp[i - 1] + cur - 2 * inv[i][j] + (j - i + 1) * (j - i) / 2});
fwt.update(pos[j], -1);
}
}
cout << dp[n];
return 0;
}
