// Om Namah Shivaya
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a, b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a, b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
/*
*/
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
template<typename T>
struct fenwick {
int siz;
vector<T> tree;
fenwick(int n) {
siz = n;
tree = vector<T>(n + 1);
}
int lsb(int x) {
return x & -x;
}
void build(vector<T> &a, int n) {
for (int i = 1; i <= n; ++i) {
int par = i + lsb(i);
tree[i] += a[i];
if (par <= siz) {
tree[par] += tree[i];
}
}
}
void pupd(int i, T v) {
while (i <= siz) {
tree[i] += v;
i += lsb(i);
}
}
T sum(int i) {
T res = 0;
while (i) {
res += tree[i];
i -= lsb(i);
}
return res;
}
T query(int l, int r) {
if (l > r) return 0;
T res = sum(r) - sum(l - 1);
return res;
}
};
void solve(int test_case)
{
ll n; cin >> n;
vector<ll> a(n+5);
rep1(i,n) cin >> a[i];
vector<ll> pos(n+5);
rep1(i,n) pos[a[i]] = i;
ll cost[n+5][n+5];
memset(cost,0,sizeof cost);
rep1(l,n){
// cost(l,r):
// consider the array after removing guys > r
// now we want to take all guys [l,r] to end and arrange them in order r,r-1,r-2,...,l
// cost(l,r) = cost to take to end + cost to rearrange within in end
// cost to take to end = sum(#of guys smaller than l that appear after pos[i]), for i = [l..r]
// cost to rearrange = #of inversions if we consider guys [l..r]
// our final order must be r,r-1,...,l (decreasing order)
// so definition of inversions here = #of (i,j) s.t i < j and a[i] < a[j]
vector<ll> suff(n+5);
rep1(i,n){
if(a[i] < l){
suff[i] = 1;
}
}
rev(i,n,1){
suff[i] += suff[i+1];
}
fenwick<ll> fenw(n+5);
ll take_to_end = 0;
ll inv = 0;
for(int r = l; r <= n; ++r){
take_to_end += suff[pos[r]+1];
inv += fenw.query(1,pos[r]-1);
fenw.pupd(pos[r],1);
cost[l][r] = inv + take_to_end;
}
}
vector<ll> dp(n+5,inf2);
dp[0] = 0;
rep1(i,n){
rev(j,i,1){
amin(dp[i], dp[j-1] + cost[j][i]);
}
}
ll ans = dp[n];
cout << ans << endl;
/*
ll n; cin >> n;
vector<ll> a(n);
rep(i,n) a[i] = i + 1;
do{
bool good = true;
rep(i,n-1){
if(a[i] < a[i+1] + 2){
conts;
}
good = false;
break;
}
if(good){
debug(a);
}
} while(next_permutation(all(a)));
*/
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
