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[][] points = new int[n][2];
        
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            points[a0][0] = x;
            points[a0][1] = y;
        }
        
        int isLine = -1;
        if (points[0][0] == points[1][0]){
            isLine = 0;
        }else if (points[0][1] == points[1][1]){
            isLine = 1;
        }
        
        boolean toPrint = true;
        for (int i = 1; i < n; i++){
            if (isLine == 0){
                if (points[i][0] != points[i-1][0]){
                    toPrint = false;
                    break;
                }
            }else if (isLine == 1){
                if (points[i][1] != points[i-1][1]){
                    toPrint = false;
                    break;
                }
            }else{
                toPrint = false;
                break;
            }
        }
        System.out.println(toPrint?"YES":"NO");
        
    }
}