AWS main account / sub account login

Well, AWS is a great platform, but this particular problem ate qite a lot of my brain health.

Problem description:

A. Initially, when you try to go to any "inside" page of AWS, you are requested to log in, into an AWS main account (two fields: email / password). Even if you catually want to log into an AWS sub-account (three fields: account# / login / password)

B. If you have at any time logged into an AWS sub account (three fields) - you are unable to find a login page for AWS main account (two fields).

Problem A is solved easily: you just specify your account# in the URL, and viola - you are now prompted to log into a sub-account:
https://??????????.signin.aws.amazon.com/console
, where ?????????? is your main account number.

Problem B is less obvious, I spent quite a lot of time going back and forth between links, and somehow managed to do that in the end. Logging into a sub-account ruins everything though, so at the while i'm just using two different browsers for AWS: one for the main account login, another for the sub-account login.

Hope that helps someone struggling with it - most probably that would be me, after a while, when i forget about this again. ^_^