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[15];
        int Y[]=new int[15];
        int j=0;
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            X[j]=x;
            Y[j]=y;
            j++;
        }
        int flagx=0,flagy=0;
        for(int i=0;i<j;i++)
            {
            if(X[i]==X[0])
                {
                flagx++;
            }
            if(Y[i]==Y[0])
                flagy++;
        }
        if((flagx==j)||(flagy==j))
            System.out.println("YES");
        else
            System.out.println("NO");
        
    }
}