z1 := (2,4)(3,5)(6,10)(7,11)(8,12)(9,13)(14,22)(15,23)(16,24)(17,25)(18,26)
     (19,27)(20,28)(29,38)(30,39)(32,40)(33,41)(34,42)(37,43)(44,50)(46,51)
     (47,52)(48,53)(49,54)(55,56);