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[][] ar = new int[n][2];
        HashSet<Integer>  hs = new HashSet<Integer>();
        HashSet<Integer>  hs1 = new HashSet<Integer>();
        for(int a0 = 0; a0 < n; a0++){
            hs.add(in.nextInt());
            hs1.add(in.nextInt());
        }
        if(hs.size() == 1){
            System.out.println("YES");
        }
        else if(hs1.size() == 1){
            System.out.println("YES");
        }
        else{
            System.out.println("NO");
        }
    }
}