The R in the circle on the shoe should be the mark of "registered trademark", which means that the trademark has been applied for registration with the National Trademark Office and has been reviewed and approved by the Trademark Office to become a registered trademark. The R in the circle is the first letter of English register.

register　

English ['red?st?(r)]? American ['red?st?r]

v. Register; record; register ;Registration

n. Register; record; temporary register

n. [language] register; [sound] register ventilation adjustment equipment

Example sentences:

You must register if you intend to vote.

If you intend to vote, you must register.