/************************************
 *   ??????? 				*
 *   ??????  1200012815		*
 *   ???2012.10.8				*
 ************************************/

int main()
{
	int n, i = 1, a, b, c = 0, d = 0;//i??????n??????a?b??????c??????????d????????
	cin >> n;
	while (i <= n)//??n???
	{
		for (;i <= n;i++)//???????
		{
			cin >> a >> b;
			if (a <= 140 && a >= 90 && b <= 90 && b >= 60)
			{
				c++;continue;//????????
			}
			else
			{
				if (c >= d)
				d = c;//???????????????d
				c = 0;//c??
				i++;//??????i+1
				break;
			}
		}
		if (c > d)
			d = c;//??????????????
	}
	cout << d << endl;
	return 0;
}

