#include <iostream>
#include <assert.h>
#include <stdlib.h>
#define assn(a,b,n) assert(n>=a && n<=b)

using namespace std;

int main()
{

    int n,x[10],y[10],i,flag=0;

      cin>>n;
      assn(2,10,n);

      for(i=0;i<n;i++)
       {
          cin>>x[i]>>y[i];
       }

       for(i=0;i<n-1;i++)
       {
          if((x[i+1]-x[i])!=0)
             break;
       }

       if(i==n-1)
       {
        cout<<"YES"; exit(0);
       }

       for(i=0;i<n-1;i++)
       {
          if((y[i+1]-y[i])!=0)
            break;
       }

       if(i==n-1)
       {
        cout<<"YES"; exit(0);
       }
       else
       {
         cout<<"NO";
       }

    return 0;
}