a11 := (1,2)(3,5)(6,9)(7,11)(8,13)(10,16)(12,18)(14,20)(15,22)(17,25)(19,28)
     (21,30)(24,33)(26,35)(27,37)(29,40)(31,43)(32,45)(34,47)(36,50)(38,51)
     (39,53)(41,55)(42,56)(44,59)(46,60)(48,62)(52,66)(54,67)(57,65)(58,72)
     (61,70)(63,76)(64,77)(68,81)(69,83)(71,84)(73,79)(74,85)(75,82)(87,91)
     (88,89);