#include <bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin >> n;
	set<int> X;
	set<int> Y;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin>>x>>y;
        X.insert(x);
        Y.insert(y);
    }
    if(X.size()==1  ||  Y.size()==1){
    	cout<<"YES"<<endl;
    }else{
    	cout<<"NO"<<endl;
    }
	return 0;
}