b11 := (2,4)(3,5)(6,10)(7,11)(8,12)(13,19)(14,20)(15,21)(16,22)(17,23)(18,24)
     (25,34)(26,33)(28,35)(29,36)(30,37)(32,38)(39,47)(40,48)(42,44)(43,49)
     (45,50)(52,55)(53,54);