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


int main() {
    int n;
    cin>>n;
    set<int> se;
    set<int> be;
    int brr[n],arr[n];
    for(int i=0;i<n;i++)
        cin>>arr[i]>>brr[i];
    for(int i=0;i<n;i++)
        se.insert(arr[i]);
    for(int i=0;i<n;i++)
        be.insert(brr[i]);
    if(se.size()==1 || be.size()==1)
        cout<<"YES"<<endl;
    else
        cout<<"NO"<<endl;
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}