//#pragma GCC optimize("Ofast,unroll-loops,O3")
//#pragma GCC target("avx,avx2,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,fma,tune=native")
#include<bits/stdc++.h>
//#include<bits/extc++.h>
//#pragma pack(1)
#define fast ios::sync_with_stdio(0); cin.tie(0);
#define pii pair<int,int>
#define x first
#define y second
#define N 5015
using namespace std;
//using namespace __gnu_pbds;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
//typedef tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update> order_multiset;
//typedef tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> order_set;
int dp[N],h[N],pos[N],d[N],n;
struct BIT{
int arr[N];
int lowbit(int x){
return x&-x;
}
void reset(){
for (int i=0;i<=n;i++) arr[i]=0;
}
void change(int p,int v){
for (;p<=n;p+=lowbit(p)){
arr[p]+=v;
}
}
int query(int x){
int ans=0;
for (;x>0;x-=lowbit(x)){
ans+=arr[x];
}
return ans;
}
}bit,bit2;
signed main(){
fast
cin>>n;
for (int i=1;i<=n;i++){
cin>>h[i];
pos[h[i]]=i;
dp[i]=1e9;
}
for (int i=1;i<=n;i++) bit.change(i,1);
for (int i=0;i<=n;i++){
if (i){
bit.change(1,1);
bit.change(pos[i],-1);
}
// for (int j=1;j<=n;j++) cout<<bit.query(j)<<' ';
// cout<<'\n';
int tans=0;
vector<pii>bk;
for (int j=i+1;j<=n;j++){
int np=bit.query(pos[j]);
tans+=abs(np-(i+1));
tans-=2*(j-i-1-bit2.query(pos[j]));
bit.change(1,1);
bit.change(pos[j],-1);
bit2.change(pos[j],1);
bk.push_back({1,-1});
bk.push_back({pos[j],1});
dp[j]=min(dp[j],dp[i]+tans);
//cout<<i+1<<" ~ "<<j<<" -> "<<dp[i]<<" "<<tans<<'\n';
}
bit2.reset();
for (auto j:bk) bit.change(j.x,j.y);
// cout<<dp[i]<<"\n";
}
cout<<dp[n]<<'\n';
}
