There is 5 room, a cat-like robot wants to turns off or on the room's light. The first room was lighted on the second also lighted on but the 3 and 5 was not lighted on. If the robot found a room lighted on, it will switch off the light. And when the robot found a room lighted off it will switch on the light. How many times will the robots switch off all lights? (infinity is not a number!)