import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Scanner;
import java.util.Set;
class Coin {
static class Position {
int x, y, moves;
Position(int x, int y, int moves) {
this.x = x;
this.y = y;
this.moves = moves;
}
}
public static int minMovesToTarget(int N, int[][] coins) {
List<int[]> targets = new ArrayList<>();
for (int x = 1; x <= N; x++) {
for (int y = 1; y <= 2; y++) {
targets.add(new int[]{x, y});
}
}
int totalMoves = 0;
boolean[] assigned = new boolean[2 * N];
boolean[] occupied = new boolean[2 * N];
for (int[] target : targets) {
PriorityQueue<Position> pq = new PriorityQueue<>(Comparator.comparingInt(p -> p.moves));
Set<String> visited = new HashSet<>();
for (int i = 0; i < 2 * N; i++) {
if (!assigned[i]) {
pq.offer(new Position(coins[i][0], coins[i][1], 0));
visited.add(coins[i][0] + "," + coins[i][1]);
}
}
while (!pq.isEmpty()) {
Position current = pq.poll();
if (current.x == target[0] && current.y == target[1]) {
for (int i = 0; i < 2 * N; i++) {
if (!assigned[i] && coins[i][0] == current.x && coins[i][1] == current.y) {
assigned[i] = true;
totalMoves += current.moves;
break;
}
}
break;
}
int[][] directions = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
for (int[] dir : directions) {
int newX = current.x + dir[0];
int newY = current.y + dir[1];
String newState = newX + "," + newY;
if (!visited.contains(newState)) {
visited.add(newState);
pq.offer(new Position(newX, newY, current.moves + 1));
}
}
}
}
return totalMoves;
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int N = scanner.nextInt();
int[][] coins = new int[2 * N][2];
for (int i = 0; i < 2 * N; i++) {
coins[i][0] = scanner.nextInt();
coins[i][1] = scanner.nextInt();
}
System.out.println(minMovesToTarget(N, coins));
scanner.close();
}
}
