import java.util.Scanner;

public class Solution {
	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		int n,x,y;
		int i;
		n=scan.nextInt();
		int arr[][]=new int[n][2];
		for(i=0;i<n;i++){
			arr[i][0]=scan.nextInt();
			arr[i][1]=scan.nextInt();
		}
		x=0;
		for(i=0;i<n;i++){
			if(arr[i][0]!=arr[0][0]){
				x=1;
				break;
			}
		}
		if(x==0){
			System.out.println("YES");
		}
		else{
			x=0;
			for(i=0;i<n;i++){
				if(arr[i][1]!=arr[0][1]){
					x=1;
					break;
				}
			}
			if(x==0)
				System.out.println("YES");
			else
				System.out.println("NO");
		}
	}

}