#include <bits/stdc++.h>

using namespace std;


int main()
{
    int n;
    cin >> n;
    
    bool x_eq = true, y_eq = true;
    
    int x_prev = -11, y_prev = -11;
    
    for ( int i = 0, x, y ; i < n ; ++ i )
    {
        cin >> x >> y;
        
        if ( x_prev != -11 )
            x_eq = x_eq && ( x == x_prev );
        if ( y_prev != -11 )
            y_eq = y_eq && ( y == y_prev );
        x_prev = x, y_prev = y;
    }
    cout << ( ( x_eq || y_eq ) ? "YES" : "NO" ) << endl; 
    return 0;
}