Set s of identities between relators
(zc)c-1,
(yd) (x-1d-1),
(ze) (x-1e-1),
(ya-1) (yxb-1) a-1 (xd) (xb-1) (xya-1) db-1,
(za-1) (zxc-1) a-1 (xe) (xc-1) (xza-1) ec-1,
d-1 (xyf) (xyc-1) fc-1 (zd-1) (zf) (y-1x-1c-1),
(z-1b-1) (z-1x-1f) e-1 (xzxb-1) (xzf) (xb-1) (xyx-1e-1) f