#include<bits/stdc++.h>
using namespace std;
const int N=5050;
int n,a[N],bit[2][N],pos[N],las[N][N],curr,dp[N];
void upd(int b,int id){
for (;id<N;id+=id&-id) bit[b][id]++;
}
int qry(int b,int id){
int ret=0;
for (;id;id-=id&-id) ret+=bit[b][id];
return ret;
}
int main(){
cin>>n;
for (int i=1;i<=n;i++){
cin>>a[i];
pos[a[i]]=i;
}
dp[0]=0;
for (int i=1;i<=n;i++){
for (int j=0;j<=n;j++) bit[0][j]=bit[1][j]=0;
dp[i]=INT_MAX;
for (int j=n;j>i;j--) upd(0,pos[j]);
curr=0;
for (int j=i;j;j--){
curr+=qry(0,pos[j])+qry(1,n-pos[j]+1);
dp[i]=min(dp[i],dp[j-1]+curr);
//cout<<j<<"->"<<i<<" "<<curr<<"\n";
upd(1,n-pos[j]+1);
}
//cout<<i<<": "<<dp[i]<<"\n";
}
cout<<dp[n]<<"\n";
}
