import java.util.*;
public class joi2019_ho_t4 {
static class Position {
int x, y;
Position(int x, int y) {
this.x = x;
this.y = y;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof Position)) return false;
Position p = (Position) o;
return x == p.x && y == p.y;
}
@Override
public int hashCode() {
return Objects.hash(x, y);
}
}
public static int minMovesToTarget(int N, int[][] coins) {
// Pre-calcular todos los objetivos posibles
Position[] targets = new Position[2 * N];
int idx = 0;
for (int x = 1; x <= N; x++) {
targets[idx++] = new Position(x, 1);
targets[idx++] = new Position(x, 2);
}
// Convertir monedas a Position para consistencia
Position[] coinPositions = new Position[2 * N];
for (int i = 0; i < 2 * N; i++) {
coinPositions[i] = new Position(coins[i][0], coins[i][1]);
}
// Pre-calcular todas las distancias Manhattan
int[][] distances = new int[2 * N][2 * N];
for (int i = 0; i < 2 * N; i++) {
for (int j = 0; j < 2 * N; j++) {
distances[i][j] = Math.abs(coinPositions[i].x - targets[j].x) +
Math.abs(coinPositions[i].y - targets[j].y);
}
}
// Usar un array para seguir los objetivos utilizados
boolean[] usedTarget = new boolean[2 * N];
int totalMoves = 0;
// Para cada moneda, encontrar el objetivo más cercano disponible
for (int i = 0; i < 2 * N; i++) {
int minDist = Integer.MAX_VALUE;
int bestTarget = -1;
for (int j = 0; j < 2 * N; j++) {
if (!usedTarget[j] && distances[i][j] < minDist) {
minDist = distances[i][j];
bestTarget = j;
}
}
if (bestTarget != -1) {
usedTarget[bestTarget] = true;
totalMoves += minDist;
}
}
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();
}
}
