#include<bits/stdc++.h>
using namespace std;
ifstream f("barman.in");
ofstream g("barman.out");
int n,i,j,a[605],v[605],w[605];
int main(){
  f>>n;
  for(i=1;i<=n;++i){
    f>>a[i];
    v[i]=a[i];
  }
  sort(v+1,v+n+1);
  int k=n,sol=1<<30;
  while(k--){
    int aux=v[1];
    for(i=1;i<n;++i)
      v[i]=v[i+1];
    v[n]=aux;
    for(i=1;i<=n;++i)
      w[i]=(a[i]==v[i]);
    int cost=0;
    for(i=1;i<=n;++i)
      if(a[i]!=v[i]){
        for(j=1;w[j]||a[i]!=v[j];++j);
        w[j]=1;
        cost+=20+abs(j-i);
      }
    sol=min(sol,cost);
  }
  g<<sol;
  return 0;
}