Sarah isn’t super confident with your choice, but she trusts you for some reason. After you pick that free group and start recreating Dini the 3d printer makes a hamster but then no matter what future decisions you make, the unthinkable happens Dini is all of a sudden into sampling obscure tracks from unknown artists twenty years ago. He scratches up something fierce and builds up to a drop. Sarah starts crying “where’s my Dini!” You’ll have to try another free group. What do ya pick?
F2 = {e} U S(a) U S(a^-1) U S(b) U S(b^-1)
F2 = {e} U S(a) U S(a^-1) U S(b) U S(b^-1) U S(f) U S(f^-1) U S(j) U S(j^-1)