import java.util.*;

public class Paul {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();

		int maxSum = Integer.MIN_VALUE;
		int minSum = Integer.MAX_VALUE;
		int maxDif = Integer.MIN_VALUE;
		int minDif = Integer.MAX_VALUE;

		while (n --> 0) {
			int x = sc.nextInt();
			int y = sc.nextInt();
			maxSum = Math.max(maxSum, x+y);
			minSum = Math.min(minSum, x+y);
			maxDif = Math.max(maxDif, x-y);
			minDif = Math.min(minDif, x-y);
		}

		int res = (maxSum-minSum+2) + (maxDif-minDif+2);
		if ((maxSum == minSum) != (maxDif == minDif)) res++;
		System.out.println(res);
	}
}