JR Pass for different Regions

Hello!

So I'm staying 13 days in Japan.I'm not sure if I need to buy a different JR pass for each region I will be going.
Here are the routes:

From Tokyo to Kyoto.
From Kyoto to Osaka.
From Osaka to Nagoya.
From Nagoya to Shirakawa.
From Shirakawa to Nagano.
From Nagano to Tokyo.

So, Can I buy A JR Pass for these destinations or do I have to buy different passes for each region?

Thank you!