#include<bits/stdc++.h>
using namespace std;
set < int > st1, st2;
int main()
{
    int n;
    cin >> n;

    for( int i = 0; i < n; i++ )
    {
        int x, y;
        cin >> x >> y;
        st1.insert(x);
        st2.insert(y);

    }
    if( st1.size() == 1 || st2.size() == 1 ) cout << "YES\n";
    else cout << "NO\n";
}