The answer is 76!
There are 17 train or subway companies and if you use more than 2 companies, you pay double!!

Too complicate, isn't it?
We Japanese local use these kind tool to save money and time.
http://www.hyperdia.com/en/


If you use it, you know the cheapest way, fastest way.
And we made the Tokyo train map for you!
Please download it and print it.
http://www.travelience.com/img/pdf/map.pdf
Enjoy our city!