#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n;
    cin >> n;
    vector<pair<int, int>> a(n);
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        a[a0] = {x, y};
    }
    bool ok1 = 1, ok2 = 1;
    for (int i = 1; i < n; ++i){
        if (a[i - 1].first != a[i].first)
            ok1 = 0;
        if (a[i - 1].second != a[i].second)
            ok2 = 0;
    }
    if (ok1 || ok2)
        cout << "YES";
    else
        cout << "NO";
    return 0;
}