"It is known that all computers in the class are connected to each other directly or via other computers."

So, there must be just one group of cumputers, in wich we can move from any one to any other...

I thought, that we can just cange first pupil's computer to get the answer. Where is a mistake in my thoughts?

it is wrong because
3 2
J E J
1 2
2 3

is answer
1
2 J

Why not
1
1 E
?

Edited by author 23.05.2011 11:07
I think....

Edited by author 23.05.2011 11:17