Alan and the Auto-Self-Destructing Class

Last week was very odd. I started the week with six students in a class. But one got sick and vanished, and two decided not to attend the exam on the last day. Of the three who actually turned up on the last day, one made a bit of a botch up on the exam and left early and one rendered his computer unbootable about a minute before the finish and therefore got zero marks. Fortunately the single student who survived all this carnage did pass the exam!

And so:

To the tune of "10 Green Bottles"

There were 6 new students sitting in the class.
6 new students sitting in the class.
And one new student got a bug they knew would last.
There were 5 new students sitting in the class.
5 new students sitting in the class.
But 2 new students were sure they could not pass.
There were 3 new students sitting in the class.
3 new students sitting in the class.
And 1 new student got depressed and left quite fast.
There were 2 new students sitting in the class.
2 new students sitting in the class.
And 1 new student completely stuffed his tasks.
There was 1 new student sitting in the class.
1 new student sitting in the class.
And the 1 new student actually passed!
There was 1 new graduate sitting in the class.