z1 := (2,3)(4,6)(5,8)(9,13)(10,15)(11,17)(12,19)(16,26)(18,29)(21,33)(22,35)
     (31,45)(32,47)(34,51)(36,42)(37,46)(38,56)(39,44)(40,58)(41,60)(43,62)
     (48,70)(49,71)(50,73)(54,78)(55,80)(59,86)(61,87)(63,90)(65,92)(68,93)
     (69,95)(72,101)(74,81)(75,105)(77,94)(79,110)(82,113)(83,114)(84,115)(85,
     116)(88,121)(89,122)(91,124)(96,130)(98,132)(102,137)(104,139)(106,142)
     (112,147)(119,156)(126,162)(128,164)(133,169)(136,171)(141,177)(144,181)
     (145,160)(149,151)(150,187)(154,191)(157,195)(161,200)(165,203)(168,206)
     (170,208)(174,212)(176,214)(178,211)(180,216)(183,218)(185,219)(201,217)
     (202,228)(205,225)(207,231)(213,236)(215,237)(220,232)(223,243)(224,239)
     (233,235)(240,247)(242,248)(245,249);