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