b11 := (1,2)(3,4)(5,7)(6,9)(8,12)(10,13)(11,15)(14,19)(16,21)(17,23)(18,25)(20,
     28)(22,31)(24,33)(26,35)(27,32)(29,37)(30,39)(34,43)(36,46)(38,48)(41,51)
     (42,44)(45,55)(47,50)(49,58)(52,60)(53,61)(54,59)(56,62)(57,63)(64,65);