The five posters above are demonstrating their rather distasteful miserly attitude to the human race and can be safely ignored. (In fact there is an ignore list on this forum should you want to use it.)
Thats a bit harsh checkboard.
A couple of them, yes. But really in this day and age, a simple question as asked by the OP can and should be found by a simple bit of research.
I wish I had been able to access the web when I was studying. Life would have been so much easier.
