#include <cmath>
#include <cstdio>
#include <set>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int n, i, x, y;
    cin>>n;
    set <int> X, Y;
    for(i=0; i<n;i++)
        {    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;
}