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 isHorizontal = false;
        boolean isVertical = false;
        int x1 = in.nextInt();
        int y1 = in.nextInt();
        int x2 = in.nextInt();
        int y2 = in.nextInt();
        if (x1 == x2) {
            isVertical = true;
        }
        if (y1 == y2) {
            isHorizontal = true;
        }
        if (!isVertical && !isHorizontal) {
            System.out.println("NO");
        } else {
            for(int a0 = 2; a0 < n; a0++){
                int x = in.nextInt();
                int y = in.nextInt();
                if (isVertical) {
                    if (x != x1) {
                        isVertical = false;
                        System.out.println("NO");
                        break;
                    }
                }
                if (isHorizontal) {
                    if (y != y1) {
                        isHorizontal = false;
                        System.out.println("NO");
                        break;
                    }
                }
            }
            if (isVertical || isHorizontal) {
                System.out.println("YES");
            }
        }
    }
}