#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int>vi;
#define pb push_back
#define sz(v) (int)v.size()
#define FOR(i,a,b) for(int i=a; i<b; i++)
#define ROF(i,a,b) for(int i=b-1; i>=a; i--)
void ckmin(ll &x, ll y){x=min(x,y);}
void IO(){
#ifdef LOCAL
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
#endif
}
//--------------------------------------------------------------------
const int MX=5e3+10;
int N;
ll val[MX][MX];
vi a(MX);
vi t;
void upd(int i){
for(;i<sz(t); i+=i&-i) t[i]++;
}
int get(int i){
int ans=0;
for(;i;i-=i&-i) ans+=t[i];
return ans;
}
void compute(){
FOR(l,1,N+1){
vi b;
FOR(i,1,N+1) if(a[i]>=l) b.pb(a[i]);
int n=sz(b);
vi order(N+1),nb(N+1,0);
t.assign(N+1,0);
ROF(i,0,n){
order[b[i]]=i;
nb[b[i]]=get(b[i]);
upd(b[i]);
}
val[l][l]=order[l];
FOR(r,l+1,N+1)
val[l][r]=val[l][r-1]+order[r]-nb[r];
}
}
int main(){
IO();
cin>>N;
FOR(i,1,N+1) cin>>a[i];
compute();
ll dp[N+1];
dp[0]=0;
FOR(i,1,N+1){
dp[i]=1e18;
FOR(j,0,i) ckmin(dp[i],dp[j]+val[j+1][i]);
}
cout << dp[N] << endl;
}
