import java.util.*;
class joi2019_ho_t4 {
static class State {
int x, y, moves;
State(int x, int y, int moves) {
this.x = x;
this.y = y;
this.moves = moves;
}
}
public static int minMoves(int n, int[][] positions) {
Set<String> visited = new HashSet<>();
Queue<State> queue = new LinkedList<>();
for (int[] pos : positions) {
queue.offer(new State(pos[0], pos[1], 0));
visited.add(pos[0] + "," + pos[1]);
}
int[][] targets = new int[n * 2][2];
int index = 0;
for (int x = 1; x <= n; x++) {
for (int y = 1; y <= 2; y++) {
targets[index++] = new int[]{x, y};
}
}
int totalMoves = 0;
boolean[] assigned = new boolean[n * 2];
while (!queue.isEmpty()) {
State current = queue.poll();
int closestTarget = -1, minDist = Integer.MAX_VALUE;
for (int i = 0; i < targets.length; i++) {
if (!assigned[i]) {
int dist = Math.abs(current.x - targets[i][0]) + Math.abs(current.y - targets[i][1]);
if (dist < minDist) {
minDist = dist;
closestTarget = i;
}
}
}
if (closestTarget != -1) {
totalMoves += minDist;
assigned[closestTarget] = true;
}
}
return totalMoves;
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int n = scanner.nextInt();
int[][] positions = new int[2 * n][2];
for (int i = 0; i < 2 * n; i++) {
positions[i][0] = scanner.nextInt();
positions[i][1] = scanner.nextInt();
}
scanner.close();
System.out.println(minMoves(n, positions));
}
}
