#include <bits/stdc++.h>
#define For(i,a,b) for(int i=a;i<=b;i++)
#define Forr(i,a,b) for(int i=a;i>=b;i--)
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define sz(x) ((int)x.size())
#define eb emplace_back
#define INF (1000000000000000ll);
#define int ll
using namespace std;
using ll=long long;
using pii=pair<int,int>;
#define LO(i) (i&(-i))
struct BIT{
int n;
int a[5010];
void init(int _n){
n=_n;
memset(a,0,sizeof(a));
}
void add(int i,int x){
while(i<=n){
a[i]+=x;
i+=LO(i);
}
}
int ask(int i){
int ans=0;
while(i){
ans+=a[i];
i-=LO(i);
}
return ans;
}
}bit;
int a[5010];
int pos[5010];
int no[5010];
int cost[5010][5010];
int dp[5010];
int32_t main(){
ios::sync_with_stdio(false);
cin.tie(0);
// nachoneko sama & miku sama bless me >/////<
int n; cin>>n;
For(i,1,n){
cin>>a[i];
pos[a[i]]=i;
}
For(l,1,n){
bit.init(n);
int now=0;
// int mi=l;
int cnt=0;
For(i,1,n){
if(a[i]>=l){
cnt++;
no[a[i]]=cnt;
}
}
For(r,l,n){
now+=bit.ask(pos[r]);
bit.add(pos[r],1);
now+=no[r]-(r-l+1);
cost[l][r]=now;
// cout<<l<<" "<<r<<" "<<now<<"\n";
}
}
For(i,1,n){
dp[i]=cost[1][i];
For(j,1,i-1) dp[i]=min(dp[i],dp[j]+cost[j+1][i]);
}
cout<<dp[n]<<"\n";
return 0;
}
