#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int n,x,y,prevx,prevy;
    int flag=0;
    cin>>n;
    for(int i=0;i<n;i++)
    {
        cin>>x>>y;
        if(i==0)
           {
             prevx=x;
                 prevy=y;
        }
        else if(i==1)
           {
             if(prevx==x)
               {
                 flag=1;
             }
            else if(prevy==y)
               {
                 flag=2;
             }
        }
        else{
            if(flag==1)
                {
                if(prevx!=x)
                    flag=0;
            }
            else if(flag==2)
                {
                if(prevy!=y)
                    flag=0;
            }
            if(flag==0)
                continue;
            
        }
    }
        if(flag==0)
            cout<<"NO"<<endl;
        else cout<<"YES"<<endl;
    return 0;
}