//vivekmufc

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

typedef long long ll;
typedef pair<int, int> ii;
#define pb(x)                        push_back(x)
#define endl                         '\n'
#define INF                         (int)1e9
int mod = 1000000007;

#define N        100005

int main()
{
      std::ios::sync_with_stdio(false);
      int n;
      cin>>n;


      set<ii> st;
      int flg1 = 1, flg2 = 1;
      int x,y;
      cin>>x>>y;
      for (int i = 0; i < n-1; ++i)
      {
            int a,b;
            cin>>a>>b;
            if(a!=x)
                  flg1 = 0;
            if(b!=y)
                  flg2 = 0;
      }

      if(flg1 || flg2)
            cout<<"YES";
      else
            cout<<"NO";
}