#include <iostream>

using namespace std;

int main() {
    int n;
    cin >> n;
    int x0, y0, x1, y1;
    cin >> x0 >> y0 >> x1 >> y1;
    bool vert = (x0 == x1), hor = (y0 == y1);    
    for (int i = 0; i < n - 2 && (vert || hor); i++) {
        int x;
        int y;
        cin >> x >> y;
        
        vert = vert && x == x0;
        hor = hor && y == y0;
    }
    
    cout << (vert || hor ? "YES" : "NO") << endl;
}