How to find Branch number in Active Directory by C# ?

Hi,

Could anyone provide any information about how to find Branch number in Active Directory(AD) account by C#?

For example, I have an AD account: abc\xyz. At my computer, when I login it, I can get my branch number from:

Control Panel -> System -> Advanced tab - > Enviroment Variables.

At the part of "User Variables for xyz", one variable of Branch has its value : 55.

My question is how to user C# to find this Branch number by using is my AD account. 

Thanks.