#include <bits/stdc++.h>
using namespace std;
template <typename T>
class fenwick {
public:
vector<T> fenw;
int n;
fenwick(int _n) : n(_n) {
fenw.resize(n);
}
void modify(int x, T v) {
while (x < n) {
fenw[x] += v;
x |= (x + 1);
}
}
T get(int x) {
T v{};
while (x >= 0) {
v += fenw[x];
x = (x & (x + 1)) - 1;
}
return v;
}
};
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<int> h(n);
for (int i = 0; i < n; i++) {
cin >> h[i];
}
vector<int> pos(n + 1);
for (int i = 0; i < n; i++) {
pos[h[i]] = i;
}
vector<vector<long long>> f(n + 1, vector<long long>(n + 1));
fenwick<int> fenw(n);
for (int i = 1; i <= n; i++) {
fenwick<int> pref(n);
for (int j = i; j <= n; j++) {
f[i][j] = f[i][j - 1] + fenw.get(n - 1) - fenw.get(pos[j]) + pref.get(pos[j]);
pref.modify(pos[j], +1);
}
fenw.modify(pos[i], +1);
}
const int inf = 1e9;
vector<long long> dp(n + 1, inf);
dp[0] = 0;
for (int i = 0; i < n; i++) {
for (int j = i + 1; j <= n; j++) {
dp[j] = min(dp[j], dp[i] + f[i + 1][j]);
}
}
cout << dp[n] << '\n';
return 0;
}
