b21 := (1,2,4)(3,5,8)(6,9,13)(7,10,15)(11,16,22)(12,17,24)(14,19,26)(18,20,25)
     (21,27,31)(23,29,34)(28,32,33)(30,35,40)(36,41,46)(37,42,48)(38,43,50)
     (39,44,51)(45,52,60)(47,54,63)(49,56,66)(53,61,62)(55,64,73)(57,67,59)
     (58,68,78)(65,74,82)(69,79,88)(70,80,87)(71,76,84)(72,81,91)(75,83,94)
     (77,85,97)(86,98,96)(89,100,111)(90,101,113)(92,103,116)(93,104,118)(95,
     106,112)(99,109,110)(102,114,127)(105,119,120)(107,121,134)(108,122,136)
     (115,128,143)(117,130,146)(123,137,154)(124,138,156)(125,139,158)(126,
     140,160)(129,144,145)(131,147,166)(132,148,168)(133,149,170)(135,151,173)
     (141,161,142)(150,171,172)(152,174,195)(153,175,196)(155,177,199)(157,
     178,201)(159,180,204)(162,183,208)(163,184,210)(164,185,212)(165,186,214)
     (167,188,217)(169,190,219)(176,197,225)(179,202,203)(181,205,231)(182,
     206,233)(187,215,216)(189,218,200)(191,220,246)(192,221,248)(193,222,250)
     (194,223,245)(198,226,252)(207,234,261)(209,236,264)(211,238,267)(213,
     240,270)(224,227,253)(228,254,282)(229,255,284)(230,256,241)(232,258,288)
     (235,262,263)(237,265,295)(239,268,269)(242,271,301)(243,272,303)(247,
     274,306)(249,276,309)(251,278,311)(257,286,287)(259,289,321)(260,290,322)
     (266,296,327)(273,304,305)(275,307,336)(277,298,310)(279,312,341)(280,
     313,343)(281,314,345)(283,316,348)(285,318,351)(291,323,355)(292,324,356)
     (293,325,358)(294,326,360)(297,328,363)(299,329,365)(300,330,367)(302,
     332,370)(308,337,374)(315,346,347)(317,349,385)(319,352,389)(320,353,391)
     (331,368,369)(333,371,402)(334,372,390)(335,373,404)(338,375,364)(339,
     376,407)(340,377,409)(342,379,412)(344,381,414)(350,386,418)(354,392,421)
     (357,395,424)(361,396,426)(362,397,427)(366,387,419)(378,410,411)(380,
     413,408)(382,415,438)(383,416,440)(384,417,399)(388,398,428)(394,422,447)
     (400,429,453)(401,430,437)(403,431,455)(405,433,458)(406,434,460)(420,
     444,435)(423,448,469)(425,449,470)(432,456,478)(439,462,485)(441,464,488)
     (442,465,489)(443,466,491)(445,468,446)(450,471,495)(451,472,496)(452,
     473,498)(454,475,501)(457,479,503)(459,481,480)(461,483,484)(463,486,507)
     (467,492,494)(474,499,500)(476,502,517)(477,490,511)(482,504,510)(487,
     508,520)(497,509,521)(505,518,515)(506,519,514)(512,522,525)(513,523,516);