It's a convention to call a variable n, you can call it anything

After all, before we start counting,we haven't counted anything yet.Calling this variable n is just a convention.I could have called it almost anything.Now, line 2 demarks the start of loop,a sequence of steps that will repeat some number of times.So, in our example, the step we're taking is counting people in the room.Beneath line 2 is line 3,which describes exactly how we'll go about counting.