static void Main(string[] args)
{
TestSystem testSystem = new TestSystem();
int n = int.Parse(Console.ReadLine());
try
{
for (int i = 0; i < n; i++)
{
string[] commands = Console.ReadLine().Split();
if (commands[0] == "Add")
{
testSystem.Add(commands[1]);
}
else if (commands[0] == "Remove")
{
testSystem.Remove(commands[1]);
}
else if (commands[0] == "Notify")
{
testSystem.Notify(commands[1]);
}
else
{
throw new NotImplementedException();
}
}
}
catch (ArgumentException e)
{
Console.WriteLine(e.Message);
}
}