//Nishant Arora
//I love KS.
#include<bits/stdc++.h>
using namespace std;
int main()
    {
    int n;    
    cin>>n;
    int a[n],b[n];
    for(int i=0;i<n;i++)cin>>a[i]>>b[i];
    int flag=1;
    for(int i=0;i<n-1;i++){if(a[i]!=a[i+1])flag=0;}
    
    if(flag==1){cout<<"YES";return 0;}
    flag=1;
    for(int i=0;i<n-1;i++){if(b[i]!=b[i+1])flag=0;}
    if(flag==1){cout<<"YES";return 0;}
    cout<<"NO";
}