Originally Posted by Globaliser

So long as that is what it says on the box that's somewhere between the plug and the laptop (which is itself a transformer), you will be absolutely fine. Modern power supplies which are so marked were intended to solve exactly the problem that you thought you might have. You just need to have a physical adaptor (very cheap) that changes the shape of your plug so that it will fit into the wall socket.

(BTW, it's "50-60 Hz", not "50-60 mhz". 1 Hertz = 1 cycle per second. Computer processors are the things that are driven at many hundred MHz or more. 1 MHz or megaHertz = 1 million cycles per second. 1 GHz or gigaHertz = 1000 MHz = 1 billion cycles per second.)