#include <bits/stdc++.h>
 using namespace std;

#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define LL long long int
#define pb push_back 
#define mp make_pair
#define PII pair<int,int>
#define PLL pair<LL,LL>
#define PIS pair< int,string>

#define VI vector <int>::iterator it;
#define VL vector <LL>::iterator lt;
#define VPI vector <PII>::iterator pit;
#define VPL vector <PLL>::iterator plt; 

#define test int t;cin>>t;while(t--)
#define ff first
#define ss second
#define INF 1000000000
#define INIT(a,x) memset(a,x,sizeof(a))
#define input(a,n) for(i=1;i<=n;i++)cin>>a[i];
#define output(a,n) for(i=1;i<=n;i++)cout<<a[i]<<" ";



int main() {
	fast 
	int n,i,j,k,z,x,y,s;
	cin>>n;
    int a[n+1],b[n+1];
    for(i=0;i<n;i++)
        {
          cin>>a[i]>>b[i];
    }
    bool f=true,g=true;
    for(i=1;i<n;i++)
        {
         if(a[i]!=a[i-1])
             {
             f=false;
             break;
         }
    }
   for(i=1;i<n;i++)
        {
         if(b[i]!=b[i-1])
             {
             g=false;
             break;
         }
    }
    if(f || g)
        cout<<"YES";
    else
        cout<<"NO";
	return 0;
}