.
...^^^also, if you want to join the club of people who spend way too much time thinking about this stuff, you can go to an online gear calculator, input your chainwheels, wheel and tyre size, crank length, and potential replacement cog cluster numbers and derive a little chart that gives you the results. Thus you can search for your own personal ideal gearing.

Or if it's working well for you, just count what you got and try to replace with the same or similar.