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 = new int[n];
        int[] yy = new int[n];
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            xx[a0] = x;
            yy[a0] = y;
        }
        
        boolean bool1 = true;
        boolean bool2 = true;
        for (int i = 1; i < n; i++){
                if (xx[i] != xx[i-1]) bool1 = false;
                if (yy[i] != yy[i-1]) bool2 = false;
        }
        if (bool1 || bool2)System.out.println("YES");
        else System.out.println("NO");
    }
}