import java.util.*;
class Main {
static int totalCoins;
static final long INF = (long) 1e18;
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
totalCoins = scanner.nextInt();
List<int[]> positions = new ArrayList<>();
for (int i = 0; i < 2 * totalCoins; i++) {
positions.add(new int[]{scanner.nextInt(), scanner.nextInt()});
}
scanner.close();
DPCount(positions);
}
static void DPCount(List<int[]> positions) {
Map<Set<Integer>, Long> coinStates = new HashMap<>();
coinStates.put(new HashSet<>(), 0L);
for (int placedCoins = 1; placedCoins <= 2 * totalCoins; placedCoins++) {
Map<Set<Integer>, Long> newCoinStates = new HashMap<>();
for (Map.Entry<Set<Integer>, Long> stateEntry : coinStates.entrySet()) {
Set<Integer> currentPlacedCoins = stateEntry.getKey();
long currentMoves = stateEntry.getValue();
for (int coinIndex = 0; coinIndex < 2 * totalCoins; coinIndex++) {
if (!currentPlacedCoins.contains(coinIndex)) {
Set<Integer> newPlacedCoins = new HashSet<>(currentPlacedCoins);
newPlacedCoins.add(coinIndex);
int[] coinPosition = positions.get(coinIndex);
long moveCost;
if (placedCoins > totalCoins) {
moveCost = Math.abs(coinPosition[0] - (placedCoins - totalCoins))
+ Math.abs(coinPosition[1] - 2);
} else {
moveCost = Math.abs(coinPosition[0] - placedCoins)
+ Math.abs(coinPosition[1] - 1);
}
long updatedCost = currentMoves + moveCost;
long previousCost = newCoinStates.getOrDefault(newPlacedCoins, INF);
newCoinStates.put(newPlacedCoins, Math.min(previousCost, updatedCost));
}
}
}
coinStates = newCoinStates;
}
long result = INF;
for (long cost : coinStates.values()) {
result = Math.min(result, cost);
}
System.out.println(result);
}
}
