import java.util.Scanner;

public class Solution {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        boolean v1=true,v2=true,h=false;
        int pa=0,pb=0;
        for(int i=0; i<n; i++){
                int a = sc.nextInt();
                int b = sc.nextInt();
                if(a==b) h = true;
                if(i>0){
                    if(a!=pa) v1=false;
                    if(b!=pb) v2=false;
                } 
                pa =a;
                pb = b;
        }
        if(v1 || v2 || h) System.out.println("YES");
        else System.out.println("NO");
        
    }
}