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 f = true;
        boolean f2 = true;
        int x = in.nextInt();
        int y = in.nextInt();
        for(int a0 = 1; a0 < n; a0++){
            int x1 = in.nextInt();
            int y1 = in.nextInt();
            if(x != x1)
                f = false;
            if(y != y1)
                f2 = false;
        }
        System.out.println((f||f2)?"YES":"NO");
    }
}