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 lastX = 0;
        int lastY = 0;
        lastX = in.nextInt();
        lastY = in.nextInt();
        boolean xDifferent = false;
        boolean yDifferent = false;
        for(int a0 = 1; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if (lastX != x) {
                xDifferent = true;
            }
            if (lastY != y) {
                yDifferent = true;
            }
        }
        if (xDifferent && yDifferent) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    }
}