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) throws Exception {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));
        int n = ip(in.readLine());
        int[] x=new int[n];
        int[] y=new int[n];
        for (int i=0; i<n; i++) {
            int[] a = ia(in.readLine(), 2);
            x[i]=a[0];
            y[i]=a[1];
        }
        int flag1=0, flag2=0;
        for (int i=1; i<n; i++) {
            if (x[i]!=x[i-1]) {
                flag1=1;
            }
            if (y[i]!=y[i-1]) {
                flag2=1;
            }
        }
        if (flag1==0 || flag2==0) {
            out.write("YES\n");
        }
        else {
            out.write("NO\n");
        }
        out.flush();
    }
    
    private static int ip(String s) {
        int n = Integer.parseInt(s);
        return n;
    }
    
    private static long lp (String s) {
        long n = Long.parseLong(s);
        return n;
    }
    
    private static double dp (String s) {
        double n = Double.parseDouble(s);
        return n;
    }
    
    private static int[] ia (String s, int n) {
        String[] s1 = s.split(" ");
        int[] A = new int[n];
        for (int i=0; i<n; i++) {
            A[i] = Integer.parseInt(s1[i]);
        }
        return A;
    }
    
    private static long[] la(String s, int n) {
        String[] s1 = s.split(" ");
        long[] A = new long[n];
        for (int i=0; i<n; i++) {
            A[i] = Long.parseLong(s1[i]);
        }
        return A;
    }
    
    private static double[] da (String s, int n) {
        String[] s1 = s.split(" ");
        double[] A = new double[n];
        for (int i=0; i<n; i++) {
            A[i] = Double.parseDouble(s1[i]);
        }
        return A;
    }
}