#include <iostream>

using namespace std;

int main()
{
	int n;
	cin >> n;
	int flag1 = 0, flag2 = 0;
	int x,y;
	cin >> x >> y;
	n = n-1;
	while(n--)
	{
		int temp1,temp2;
		cin >> temp1 >> temp2;
		if(temp1 != x)
			flag1 = 1;
		if(temp2 != y)
			flag2 = 1;
	}
	if(flag1 == 0 || flag2 == 0)
		cout << "YES\n";
	else
		cout << "NO\n";
	return 0;
}