#include <bits/stdc++.h>
using namespace std;

ifstream in("barman.in");
ofstream out("barman.out");

const int NMAX = 600, INF = 2e9;

int n, ans;
int sol[NMAX + 5], a[NMAX + 5];
bool vis[NMAX + 5];

int main()
{
    in >> n;

    int tmp;
    for(int i = 1; i <= n; i++)
    {
        in >> a[i];
        sol[i] = a[i];
    }

    sort(sol + 1, sol + n + 1);

    ans = INF;
    for(int p = 1; p <= n; p++)
    {
        int minim = 0;
        for(int i = 1; i <= n; i++)
            if(a[i] == sol[i]) vis[i] = true;
            else vis[i] = false;

        for(int i = 1; i <=n; i++)
        {
            if(a[i] != sol[i])
            {
                for(int j = 1; j <= n; j++)
                    if(a[i] == sol[j] && !vis[j])
                    {
                        minim += 20 + abs(i - j);
                        vis[j] = true;
                        break;
                    }
            }
        }

        ans = min(ans, minim);
        rotate(sol + 1, sol + 2, sol + n + 1);
    }

    out << ans << '\n';

    return 0;
}