import java.io.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Scanner;
import java.util.StringTokenizer;

public class code1 {
	public static void main(String[] agrs) {
		
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		sc.nextLine();
		int[] x_cor = new int[21];
		int[] y_cor = new int[21];
		for (int i = 0; i < n; i++) {
			String[] s = sc.nextLine().split(" ");
			int x = Integer.parseInt(s[0]);
			int y = Integer.parseInt(s[1]);
			x += 10;
			y += 10;
			x_cor[x] += 1;
			y_cor[y] += 1;
		}
		int mx = -1, my = -1;
		for (int i = 0; i <= 20; i++) {
			if (mx < x_cor[i]) mx = x_cor[i];
			if (my < y_cor[i]) my = y_cor[i];
		}
		if (mx == n && my != n) {
			System.out.println("YES");
		} else if (my == n && mx != n) {
			System.out.println("YES");
		} else {
			System.out.println("NO");
		}
	}
	
//	private class point implements Comparable<point> {
//		int x, int y;
//	}
}