#include <bits/stdc++.h>

using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<pair<int,int> > a(n);

    bool ans1 = true, ans2 = true;

    for (int i = 0; i < n; ++i) {
        cin >> a[i].first >> a[i].second;
        if (i == 0)
            continue;

        ans1 &= a[i].first == a[i - 1].first;
        ans2 &= a[i].second == a[i - 1].second;
    }

    cout << (ans1 || ans2 ? "YES" : "NO") << "\n";

    return 0;
}