#include <fstream>
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <string>
#include <iomanip>

using namespace std;

typedef long long ll;



int main() {


    ifstream fin;
    ofstream fout;
    fin.open("input.txt");
    fout.open("output.txt");

    int n;
    cin >> n;

    vector<pair<int,int> > v(n);

    for(int i = 0; i < n; i++)
    {
        cin >> v[i].first >> v[i].second;
    }

    bool left = true;
    bool right = true;

    for(int i = 1; i < n; i++)
    {
        if(v[i].first != v[i-1].first) left = false;
        if(v[i].second != v[i-1].second) right = false;
    }

    if(left || right)
    {
        cout << "YES";
    } else cout << "NO";


    fin.close();
    fout.close();

    return 0;
}