/*
jai shree ram _/\_
A hacker from NITP
*/

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

#define mod 1000000007
typedef set<string> ss;
typedef vector<int> vs;
typedef map<int,char> msi;
typedef pair<int,int> pa;
typedef long long int ll;

bool flag1,flag2;
int n,a,b,x,y,i;
int main()
{
	//freopen("i.in", "r", stdin);
  	//freopen("o.out", "w", stdout);
  	ios_base::sync_with_stdio(false);
  	cin.tie(0);
  	cin>>n>>a>>b;
  	flag1=flag2=1;
  	for(i=1;i<n;i++)
  	{
  		cin>>x>>y;
  		if(x!=a)
  		flag1=0;
  		if(y!=b)
  		flag2=0;
  	}
  	if(flag1 || flag2)
  		cout<<"YES\n";
  	else
		cout<<"NO\n";
	return 0;
}