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 f=0;
        HashSet<Integer>hs1=new HashSet<Integer>();
          HashSet<Integer>hs2=new HashSet<Integer>();
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            hs1.add(x);
            hs2.add(y);
        }
        if(hs1.size()==1||hs2.size()==1)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}