I came accross this problem in an old maths textbook of my fathers and its really annoying me because i cant seem to work it out
can anyone do it?:

A particular species of chameleon comes in three colours: red, blue and green. Whenever two chameleons of different colours meet they change colour, both changing to the third colour. Thus if a red chameleon meets a blue chameleon they both change to green. When two chameleons of the same colour meet, neither change colour. If there are originally 13 red chameleons, 14 blue chameleons and 15 green chameleons is it possible for all the chameleons to become the same colour? Generalise.

Good Luck!