#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, i, j;
  cin >> n;
  vector<int> ct[n + 1];
  for (i = 0; i < 2 * n; i++) {
    int x;
    cin >> x;
    ct[x].push_back(i);
  }
  int p1 = 0, p2 = 0;
  long long ans = 0;
  for (i = 1; i <= n; i++) {
    ans += min(abs(ct[i][0] - p1) + abs(ct[i][1] - p2),
               abs(ct[i][0] - p2) + abs(ct[i][1] - p1));
    p1 = ct[i][0];
    p2 = ct[i][1];
  }
  cout << ans << endl;
}
