Caanot login to mailbox because cant login to firefox.

Hello, i have an stupideouse situation. I stored my email password in my firefox account years ago. Now, after i-ve reinstalled my OS i need to login to firefox to get access to all my accounts, but to login in firefox i need to approve myself by using code in my email...

So, the problem is: to login in firefox i need to login in my mailbox. To login in my mailbox i need to login in firefox. Is there anythink i can do in this situation?