Hi Anne93,
I'm afraid that there isn't any required pattern or length to help you recall the Master Password. Ultimately, if you cannot remember it, the only option would be to delete both the Master Password and the logins saved on your device. Please see this support article for instructions on how to do this:
https://support.avast.com/article/163/However, I can see that you have previously synchronized your logins across both your PC and your Samsung Android device. If you are able to unlock Passwords on one of these devices (the Master Password can be different on both of them), you can use the unlocked device to authorize the other device and restore your logins after deleting the Master Password. Please see the
Synchronize subsequent devices section in this support article for how to do this:
https://support.avast.com/article/255/#idt_020If this is not possible, you might try to restore the logins using the backup email that was sent when you originally synchronized the first device (on 26-Jun-2017). The process for using the backup email does require the original Master Password, so this may only be useful if you think you may have changed the Master Password on the locked device at some point. Please see this support article for instructions on doing this:
https://support.avast.com/article/92/