#include <fstream>
#include <iostream>
#include <algorithm>

using namespace std;

ifstream in("barman.in");
ofstream out("barman.out");
int n;
int v[1205];
int temp[1205];
int sorted[1205];
int used[1205];
int INF = (1 << 30);

int cost(int i, int j)
{
    if(i == j)
    {
        return 0;
    }

    if(i > n) i -= n;
    if(j > n) j -= n;

    int ans = 20 + abs(i - j);
    return ans;
}

int main()
{
    in>>n;
    for(int i = 1; i<=n; i++)
    {
        in>>v[i];

        sorted[i] = v[i];
        v[n + i] = v[i];
    }

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

    int ans = INF;
    for(int start = 1; start <= n; start++)
    {
        int st = start;
        int dr = start + n - 1;

        for(int i = st; i<=dr; i++)
        {
            temp[i] = v[i];
            used[i] = 0;
        }

        int sum = 0;
        for(int i = st; i<=dr; i++)
        {
            for(int j = st; j<=dr; j++)
            {
                if(used[j] == 0 && temp[i] == sorted[j - st + 1])
                {
                    used[j] = 1;

                    sum += cost(i, j);
                    break;
                }
            }
        }

        ans = min(ans, sum);
    }

    out<<ans;

    return 0;
}