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 xx = -1;
        int yy = -1;
        boolean horiz = true;
        boolean vert = true;
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if (a0 != 0 && xx != x) {
              horiz = false;
            }
            if (a0 != 0 && yy != y) {
              vert = false;
            }
            xx = x;
            yy = y;
        }
        if (horiz || vert) {
          System.out.println("YES");
        } else {
          System.out.println("NO");
        }
    }
}