import java.util.*;
class joi2019_ho_t4 {
static class Node {
int x, y, cost;
Node(int x, int y, int cost) {
this.x = x;
this.y = y;
this.cost = cost;
}
}
public static int minMoves(int N, int[][] positions) {
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});
}
}
boolean[] assigned = new boolean[2 * N];
boolean[] targetAssigned = new boolean[2 * N];
PriorityQueue<int[]> pq = new PriorityQueue<>(Comparator.comparingInt(a -> a[2]));
int totalCost = 0;
for (int i = 0; i < 2 * N; i++) {
int minDist = Integer.MAX_VALUE, targetIdx = -1;
for (int j = 0; j < 2 * N; j++) {
if (targetAssigned[j]) continue;
int dist = Math.abs(positions[i][0] - targets.get(j)[0]) + Math.abs(positions[i][1] - targets.get(j)[1]);
if (dist < minDist) {
minDist = dist;
targetIdx = j;
}
}
totalCost += minDist;
targetAssigned[targetIdx] = true;
}
return totalCost;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int N = sc.nextInt();
int[][] positions = new int[2 * N][2];
for (int i = 0; i < 2 * N; i++) {
positions[i][0] = sc.nextInt();
positions[i][1] = sc.nextInt();
}
System.out.println(minMoves(N, positions));
sc.close();
}
}
