Hey I'm having trouble with this math question,

Rachael purchases a townhouse 'off the plan' and the builder offers her a choice of colors for interior painting. The walls can be cream, light blue or light green, and the ceilings vivid white or off-white. Different colors may be chosen for different rooms but only two colors can be used in any room (one for the ceiling and one for the walls). The townhouse consists of four rooms; living room, bedroom, kitchen and bathroom.

What is the probability that at least 2 rooms have identical color schemes.

Thanks for the help