This is ordinary example for Class B Example:
Network id: 188.8.131.52
But in subnet are the classes less IP. So for the following IP It is not for class A, B, C.
Network id: 184.108.40.206
Host id: 0.0.255.255
Subnet mask: 255.255.240.0
If you doubt see the post: how to calculate the subnet mask value