import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
    public void yaxis(int ar[],int p){
        int flag=0;
        for(int j=1;j<p;j++){
            if(ar[j]==ar[j-1]){
                flag=1;
            }
            else{
                flag=0;
            }
        }
        if(flag==1){
            System.out.println("YES");
        }
        else{
            System.out.println("NO");
        }
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int x1[]=new int[n];
        int y1[]=new int[n];
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            x1[a0]=x;
            y1[a0]=y;
            
        }
        int flag=0;
       for(int i=1;i<n;i++){
           if(x1[i]==x1[i-1]){
               flag=1;
           }
            else{
                flag=0;
                Solution sc=new Solution();
                sc.yaxis(y1,n);
                break;
            }
       }
        if(flag==1){
            System.out.println("YES");
        }
    }
}