import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int x0 = in.nextInt();
        int y0 = in.nextInt();
        String solX = "YES";
        String solY = "YES";
        for(int a0 = 1; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if (x!=x0){
                solX = "NO";
            }
            if (y!=y0){
                solY = "NO";
            }
        }
        if (solX.equals("YES")){
            System.out.println(solX);
        } else {
            System.out.println(solY);

        }
    }
}