#include <bits/stdc++.h>
using namespace std;
int blacks(int *pos, int n);
int whites(int *pos, int n);
int main() {
  int n;
  cin >> n;
  int board[100];
  for (int i = 0; i < n; i++) {
    board[i] = 0;
  }
  for (int i = 0; i < n / 2; i++) {
    int temp;
    cin >> temp;
    board[temp - 1] = 1;
  }
  cout << min(blacks(board, n), whites(board, n));
}
int blacks(int *pos, int n) {
  int i = 0;
  int label = 0;
  int result = 0;
  while (i < n) {
    if (pos[i] == 1) {
      result += abs(i - label);
      label += 2;
    }
    i++;
  }
  return result;
}
int whites(int *pos, int n) {
  int i = 0;
  int label = 1;
  int result = 0;
  while (i < n) {
    if (pos[i] == 1) {
      result += abs(i - label);
      label += 2;
    }
    i++;
  }
  return result;
}
