/*
 * Volcanoes.java
 * 
 * Copyright 2022 ACM CTU Contest Team 53 <cteam053@acm-new.fiit.stuba.sk>
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 * 
 * 
 */
import java.util.*;

public class Volcanoes {
	public static class Volcano {
		int x;
		int y;
		
		public Volcano(int x, int y) {
			this.x = x;
			this.y = y;
		}
	}
	
	public static void sortByX(List<Volcano> volcs) {
		for (int i = 0; i < volcs.size(); i++) {
			for(int j = i + 1; j < volcs.size(); j++) {
				if (volcs.get(j).x < volcs.get(i).x) {
					Collections.swap(volcs, i, j);
				}
			}
		}
	}
	public static void sortByY(List<Volcano> volcs) {
		for (int i = 0; i < volcs.size(); i++) {
			for(int j = i + 1; j < volcs.size(); j++) {
				if (volcs.get(j).y < volcs.get(i).y) {
					Collections.swap(volcs, i, j);
				}
			}
		}
	}
	
	public static void sortVolcs(List<Volcano> volcs) {
		sortByY(volcs);
		sortByX(volcs);
	}
	
	public static void printVolcs(List<Volcano> volcs) {
		System.out.println("Volcanoes:");
		for (int i = 0; i < volcs.size(); i++) {
			System.out.println(volcs.get(i).x + " " + volcs.get(i).y);
		}
	}
	
	
	public static int pathBetween(Volcano one, Volcano two) {
		int path = 0;
		path += Math.max(one.x, two.x) - Math.min(one.x, two.x);
		path += Math.max(one.y, two.y) - Math.min(one.y, two.y);
		return path;
	}
	public static int calcPath(List<Volcano> volcs) {
		int sum = 0;
		for(int i = 0; i < volcs.size() - 1; i++) {
			sum += pathBetween(volcs.get(i), volcs.get(i + 1));
		}
		return sum;
	}
		
	public static void main (String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		List<Volcano> volcanoes = new ArrayList<>();
		for(int i =0; i < n; i++) {
			Volcano volc = new Volcano(scan.nextInt(), scan.nextInt());
			volcanoes.add(volc);
		}
		//System.out.println(calcPath(volcanoes));
		//printVolcs(volcanoes);
		sortVolcs(volcanoes);
		//printVolcs(volcanoes);
		
		System.out.println(calcPath(volcanoes));
	}
}