How to get Active Directory Attributes not represented by the UserPrincipal class

What I mean is that right now I am using System.DirectoryServices.AccountManagement and if I use UserPrincipal class I only see the Name, Middle Name, etc

so in my codes it like

UserPrincipal myUser = new UserPrincipal(pc);
myUser.Name = "aaaaaa";
myUser.SamAccountName = "aaaaaaa";
.
.
.
.
myUser.Save();

How would I see the attribute like mobile or info?