#include <stdio.h>
#include <algorithm>
#define NMax 610
using namespace std;

const char IN[]="barman.in",OUT[]="barman.out";

int N,L,Rez=(1<<30);
int v[NMax],s[NMax],o[NMax];

int dist(int x,int y)
{
	if (x>y) swap(x,y);
	return min(y-x,N-y+x);
}

void rotate()
{
	int i,x;
	x=s[1];
	for (i=2;i<=N;++i) s[i-1]=s[i];
	s[N]=x;
}

int solve()
{
	int i,ret=0;
	for (i=1;i<=N;++i) o[i]=0;

	for (i=1;i<=N;++i)
		if (v[i]==s[i])
			o[i]=true;

	for (i=1;i<=N;++i)
	{
		if (v[i]==s[i]) continue;
		for (int j=1;j<=N;++j)
			if (v[i]==s[j] && !o[j])
			{
				ret+= 20+abs(i-j);
				o[j]=true;
				break;
			}
	}
	return ret;
}

int main()
{
	int i;
	freopen(IN,"r",stdin);
	scanf("%d",&N);
	for (i=1;i<=N;++i) scanf("%d",v+i),s[i]=v[i];
	fclose(stdin);

	sort(s+1,s+N+1);

	for (int j=1;j<=N;++j)
	{
		if (j!=1) rotate();
		Rez=min(Rez,solve());
	}

	freopen(OUT,"w",stdout);
	printf("%d\n",Rez);
	fclose(stdout);

	return 0;
}