#include <bits/stdc++.h>

using namespace std;

int main()
{
    int x[100],y[100];
    int n;
    while(cin >> n){
		for(int i=0;i<n;i++)
			cin >> x[i] >> y[i];
		bool isXOK = true;
		bool isYOK = true;

		for(int i=1;i<n;i++)
		{
			if(x[i] == x[i-1])
				continue;
			else{
				isXOK = false;
				break;
			}
		}

		for(int i=1;i<n;i++)
		{
			if(y[i] == y[i-1])
				continue;
			else{
				isYOK = false;
				break;
			}
		}

		if(isXOK || isYOK){
			cout << "YES" << endl;
		}else{
			cout << "NO" << endl;
		}

    }
	return 0;
}