b21 := (1,2,5,3)(4,7,13,8)(6,10,18,11)(9,15,25,16)(12,20,30,19)(14,22,34,23)
     (17,27,41,28)(21,32)(24,36,52,37)(26,38,55,39)(29,43)(31,45,49,46)(33,42,
     59,48)(35,50,69,51)(40,56,78,57)(44,61,58,62)(47,65,87,66)(53,72,92,73)
     (54,74,93,75)(60,81,97,82)(63,85,88,67)(64,83,98,86)(68,89,79,90)(70,77)
     (71,91)(76,94)(80,96,95,84)(99,109,101,105)(100,110,107,111)(102,112)
     (104,106,113,108)(114,115,116,117);