#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define pb push_back
#define vi vector<ll>
#define f(i,a,b) for(ll i=a;i<b;i++)
#define fr(i,a,b) for(ll i=a;i>=b;i--)
#define fa(e,l) for(auto e:l)
#define all(arr) arr.begin(),arr.end()
#define pii pair<ll,ll>
#define tii tuple<ll,ll,ll>
#define coutpii(x) fa(e,x){cout<<e.first<<","<<e.second<<"\n";}cout<<"\n"
#define couttup(x) fa(e,x){ll A,B,C,D,F;tie(A,B,C,D,F)=e;cout<<A<<","<<B<<","<<C<<","<<D<<","<<F<<"\n";}cout<<"\n"
#define coutll(x) fa(e,x){cout<<e<<" ";}cout<<"\n"
#define ordered_set tree<pii,null_type,less<pii>,rb_tree_tag,tree_order_statistics_node_update>
#define vvi vector<vi>
#define v(a) vector<a>
ll func(ll a,ll b){return a+b;}
pair<vi,ll> seg(vi& arr,ll iv){
ll n=arr.size(),d=0;
while((1LL<<d)<n)d++;
ll n1=1LL<<d;
vi t(2*n1,iv);
f(i,0,n)t[n1+i]=arr[i];
fr(i,n1-1,1)t[i]=func(t[i*2],t[i*2+1]);
return {t,n1};
}
void update(vi& t,ll x,ll v,ll n1){
x+=n1;
t[x]=v;
x/=2;
while(x>0){
t[x]=func(t[x*2],t[x*2+1]);
x/=2;
}
}
ll sum(ll l,ll r,vi& t,ll n1){
l+=n1;r+=n1;
ll a=0;
while(l<=r){
if(l%2==1){a=func(a,t[l]);l++;}
if(r%2==0){a=func(a,t[r]);r--;}
l/=2;r/=2;
}
return a;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
ll n;cin>>n;
vi h(n+1),p(n+1);
f(i,1,n+1){cin>>h[i];p[h[i]]=i;}
ll m=n+2;
vi z(m,0),t1;ll n1;
tie(t1,n1)=seg(z,0);
const ll INF=(1LL<<62);
vi dp(n+1,INF);
dp[0]=0;
vi tp,tb,cp(m,0),cb(m,0);
f(i,1,n+1){
fill(all(cp),0);
fill(all(cb),0);
fill(all(z),0);
f(vv,1,i){z[p[vv]]=1;cp[p[vv]]=1;}
tie(tp,n1)=seg(z,0);
fill(all(z),0);
z[p[i]]=1;cb[p[i]]=1;
tie(tb,n1)=seg(z,0);
ll ic=0;
ll ci=(i-1)-sum(1,p[i],tp,n1);
ll bst=INF;
for(ll l=i;l>=1;l--){
bst=min(bst,dp[l-1]+ic+ci);
if(l==1)break;
ll vv=l-1;
ll A=sum(1,p[vv]-1,tb,n1);
cp[p[vv]]--;
update(tp,p[vv],cp[p[vv]],n1);
ll ps=vv-1;
ll B=ps-sum(1,p[vv],tp,n1);
ci=ci-A+B;
ll os=i-l+1;
ll ge=os-sum(1,p[vv],tb,n1);
ic+=ge;
cb[p[vv]]++;
update(tb,p[vv],cb[p[vv]],n1);
// if(i==9&&l==4)cout<<ic<<" "<<ci<<"\n";
// cout<<i<<" "<<l<<" "<<bst<<"\n";
}
dp[i]=bst;
// cout<<i<<" "<<dp[i]<<"\n";
}
cout<<dp[n]<<"\n";
}
