#include<bits/stdc++.h>
using namespace std;
#define fs first
#define sc second
#define p 1000000007
#define pb push_back
#define mp make_pair
typedef long long Int;
typedef pair<Int,Int> pii;
typedef vector<Int> vi;
typedef vector<pii> vii;
set<Int>x,y;
int main()
{
Int n;
cin>>n;
for (Int i=0;i<n;++i)
{
Int X,Y;
cin>>X>>Y;
x.insert(X);
y.insert(Y);
}
if (x.size()==1||y.size()==1)
cout<<"YES";
else
cout<<"NO";
return 0;
}