#include <iostream>
#include <iomanip>
#include <vector>
#include <cmath>
#include <algorithm>
#include <set>
#include <queue>
#include <map>
#include <stack>
#include <bitset>
#include <string>
#include <cstring>
#include <iterator>
#include <random>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef long double ld;
const ll dim = 3*1e3+7;
//const ll mod = 1e9 + 7;
const ll inf = 1e18 + 77;
#define endl "\n"
#define fi first
#define pb push_back
#define se second
#define vll vector<ll>
ll n, m;
ll ext[dim], a[dim], dp[dim], b[dim], rev[dim];
int main() {
ll k, t, u0, v0;
cin>>n;
for(int i=1; i<=n; i++){
cin>>b[i];
a[b[i]]=i;
}
dp[1]=0;
for(int i=1; i<=n; i++){
ll sum=0;
dp[i]=inf;
ll ans=0;
ll cur=0;
for(int j=1; j<i; j++){
if(a[j]>a[i])cur++;
dp[j]+=cur;
}
for(int j=i; j>=1; j--) {
sum+=rev[j];
if(a[j]<a[i])ans++;
dp[i]=min(dp[j-1]+sum+ans, dp[i]);
// cout<<dp[j-1]<<" "<<add<<endl;
}
for(int j=i-1;j>=1; j--){
if(a[j]<a[i]){rev[j]++; }
}
}
cout<<dp[n]<<endl;
return 0;
}
