#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;
#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout(T t, U...u) {cout << t << (sizeof...(u) ? ", " : ""), dout(u...);}
#else
#define debug(...) 7122
#endif
#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second
const int SIZE = 5005;
int n;
int a[SIZE], p[SIZE], add[SIZE];
int dp[SIZE];
int cnt[SIZE][SIZE], sum[SIZE][SIZE];
struct BIT {
BIT() {fill(bit, bit + n + 1, 0);}
int bit[SIZE];
void upd(int pos, int x) {
for (; pos <= n; pos += pos & -pos) bit[pos] += x;
}
int que(int pos) {
int re = 0;
for (; pos; pos -= pos & -pos) re += bit[pos];
return re;
}
int que(int l, int r) {
return que(r) - que(l - 1);
}
pair<int, int> sch(int s) {
int pos = 0, k = 0;
for (int i = __lg(n); i >= 0; i--) if (pos + (1 << i) <= n) {
int to = k + bit[pos + (1 << i)];
if (pos + (1 << i) <= s + to - 1) {
pos += 1 << i;
k = to;
}
}
return {pos, k};
}
} bit, bit2;
int Sum(int l, int r) {
return (l + r) * (r - l + 1) / 2;
}
void solve() {
cin >> n;
FOR (i, 1, n) cin >> a[i], p[a[i]] = i;
FOR (i, 1, n) {
bit = BIT();
FOR (j, i, n) {
cnt[i][j] = cnt[i][j - 1] + bit.que(p[j]);
bit.upd(p[j], 1);
}
}
FOR (i, 1, n) {
bit = bit2 = BIT();
FOR (j, i, n) {
int pos = p[j] + add[p[j]], k;
bit.upd(pos, 1);
bit2.upd(pos, pos);
tie(pos, k) = bit.sch(i - 1);
sum[i][j] = Sum(i, i + k - 1) - bit2.que(1, pos) + bit2.que(pos + 1, n) - Sum(i + k, j);
}
FOR (j, 1, p[i]) add[j]++;
}
FOR (i, 1, n) {
dp[i] = INT_MAX;
FOR (j, 0, i - 1) dp[i] = min(dp[i], dp[j] + sum[j + 1][i] + cnt[j + 1][i]);
}
cout << dp[n] << '\n';
}
int main() {
Waimai;
solve();
}
