import java.util.Scanner;


public class Solution {

    /**
     * @param args
     */
    public static void main(String[] args) {
	// TODO Auto-generated method stub

	Scanner sc = new Scanner(System.in);
	int n = sc.nextInt();
	int x[] = new int[n];
	int y[] = new int[n];
	int i;
	for(i = 0; i < n; i++)
	{
	    x[i] = sc.nextInt();
	    y[i] = sc.nextInt();
	    
	}
	int a = x[0];
	int b = y[0];
	int c = 0, d= 0;
	for(i = 1; i < n;i++)
	{
	    if(x[i] != a)
		c = 1;
	    if(y[i] != b)
		d = 1;
	}
	if(c == 0 || d == 0)
	    System.out.println("YES");
	else
	    System.out.println("NO");
    }

}