#include <fstream>
#include <algorithm>

using namespace std;

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

const int N_MAX = 600;

int n;
int time;
int timemin;

int v[1 + 2 * N_MAX];
int a[1 + N_MAX];
bool use[1 + N_MAX];

int modul(int n)
{
    if(n < 0)
        return -n;
    return n;
}

int main()
{
    cin >> n;
    for(int i = 1; i <= n; i++)
    {
        cin >> v[i];
        a[i] = v[i];
    }
    sort(v + 1, v + n + 1);
    for(int i = 1; i < n; i++)
        v[n + i] = v[i];
    timemin = 1000000000;
    for(int i = 1; i <= n; i++)
    {
        time = 0;
        for(int j = 1; j <= n; j++)
        {
            if(v[i + j - 1] != a[j])
                use[j] = 1;
            else
                use[j] = 0;
        }
        for(int j = 1; j <= n; j++)
        {
            if(v[i + j - 1] != a[j])
            {
                for(int k = 1; k <= n; k++)
                {
                    if(use[k] && v[i + k - 1] == a[j])
                    {
                        use[k] = 0;
                        time += abs(j - k) + 20;
                        break;
                    }
                }
            }
        }
        timemin = min(timemin, time);
    }
    cout << timemin;
    return 0;
}