#include <bits/stdc++.h>
using namespace std;
long long a[1000007], b[1000007], i, n, x, s, f, t;
int main() {
  cin >> n;
  for (i = 1; i <= 2 * n; i++) {
    cin >> x;
    if (a[x] == 0)
      a[x] = i;
    else if (a[x] != 0)
      b[x] = i;
  }
  s = a[1] - 1;
  for (x = 2; x <= n; x++) {
    t = a[x] - a[x - 1];
    if (t < 0) t = -t;
    s = s + t;
  }
  s = s + b[1] - 1;
  for (x = 2; x <= n; x++) {
    t = b[x] - b[x - 1];
    if (t < 0) t = -t;
    s = s + t;
  }
  cout << s;
  return 0;
}
