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 p1=0,p2=0,h1=0,h2=0,res=0;
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            
            if(x==y && x>=0){
                res=1;
                break;
            }
            if(a0>0){
                if(h1==x){
                    p1++;
                }                
                 if(h2==y){
                    p2++;
                }                
            }
                
            h1=x;
            h2=y;
        }
        System.out.println(res==1||p1==n-1||p2==n-1?"YES":"NO");
    }
}