#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ii pair<int,int>
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int nax=1e5+5;
int main() {
int n;
cin>>n;
int tab[n+1];
int pos[n+1];
for (int i = 1; i <= n; ++i)
{
cin>>tab[i];
pos[tab[i]]=i;
}
int pre[n+1][n+1];
int cost[n+1][n+1];
memset(pre,0,sizeof pre);
memset(cost,0,sizeof cost);
for (int i = 1; i <= n; ++i)
{
for (int j = 1; j <= n; ++j)
{
pre[i][j]=pre[i][j-1]+(pos[j]>pos[i]);
}
}
for (int i = 1; i <= n; ++i)
{
for (int j = i; j <= n; ++j)
{
cost[i][j]+=pre[j][i-1];
if(j>i){
cost[i][j]+=cost[i][j-1];
cost[i][j]+=(j-i);
cost[i][j]-=(pre[j][j-1]-pre[j][i-1]);
}
//cout <<i<<" "<<j<<" "<<cost[i][j]<<endl;
}
}
ll dp[n+1];
for (int i = 0; i <= n; ++i) dp[i]=1e18;
dp[0]=0;
for (int i = 1; i <= n; ++i)
{
for (int j = 1; j <= i; ++j)
{
dp[i]=min(dp[i],dp[j-1]+cost[j][i]);
}
}
cout <<dp[n]<<endl;
}
