b21 := (1,3,5,7)(2,4)(6,8,11,15)(9,12,17,22)(10,13)(14,19,25,34)(16,20,27,37)
     (18,23,31,43)(21,28,39,53)(24,32,45,62)(26,35,49,67)(29,40,55,76)(30,41,
     57,79)(33,46)(36,50,69,96)(38,52,72,101)(42,58,81,112)(44,60,84,117)(47,
     64,89,124)(48,65,91,127)(51,70,98,137)(54,74,103,144)(56,77,107,149)(59,
     82,114,73)(61,85,119,163)(63,87,80,110)(66,92,129,176)(68,94,132,178)(71,
     99,139,187)(75,104,146,196)(78,108,151,202)(83,115,158,209)(86,120,116,
     159)(88,122,167,218)(90,125,171,224)(93,130,173,226)(95,133,180,232)(97,
     135,183,235)(100,140,189,242)(102,142,192,243)(105,134,181,233)(106,147,
     118,161)(109,152)(111,154)(113,156,207,260)(121,165)(123,168,220,255)
     (126,172,223,276)(128,174,225,278)(131,164,215,270)(136,184,236,288)(138,
     185,238,291)(141,190,244,298)(143,193,246,300)(145,195,214,157)(148,198)
     (150,200,253,305)(153,204,257,308)(155,206)(160,211,265,297)(162,213,268,
     318)(166,217)(169,221,274,324)(170,222,275,326)(175,228,281,331)(177,230,
     282,321)(179,231,283,333)(182,234,286,336)(186,239,293,229)(188,240,294,
     341)(191,245,299,344)(194,247,287,203)(197,250,303,349)(199,252,249,302)
     (201,254,248,280)(205,258,310,357)(208,261,312,360)(210,263,313,361)(212,
     266,237,289)(216,271)(219,273,296,342)(227,279,330,290)(241,295,259,262)
     (251,304,350,395)(256,306,352,398)(264,314,340,368)(267,317,366,410)(269,
     319,345,388)(272,322,370,389)(277,328)(284,334,380,423)(285,335,381,425)
     (292,339,384,429)(301,346,390,433)(307,353)(309,355,400,440)(311,358,403,
     320)(315,363,408,448)(316,364,402,442)(323,371,413,415)(327,374,416,455)
     (329,376,418,457)(332,379,422,365)(337,382,426,367)(338,383,428,464)(343,
     387,424,462)(347,391)(348,392,434,466)(351,396)(354,399,438,465)(356,401,
     441,476)(359,404,444,412)(362,407,409,449)(369,411,451,477)(372,394,436,
     471)(373,414,454,397)(375,417,456,447)(377,419,458,437)(378,420,459,486)
     (385,430,467,489)(393,435,469,483)(405,445,478,495)(406,446,479,497)(421,
     460,487,496)(431,468,450,481)(439,473,463,443)(452,474)(453,470,491,485)
     (461,488,480,498)(472,493,502,482)(475,494)(484,499)(490,501,506,503)
     (500,505);