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();
        boolean xv = true, yv = true;
        int x = in.nextInt();
        int y = in.nextInt();
        for(int a0 = 1; a0 < n; a0++){
            int x1 = in.nextInt();
            int y1 = in.nextInt();
            xv = xv & (x == x1);
            yv = yv & (y == y1);
            x = x1;y=y1;   
        }
        if(xv || yv)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}