b21 := (1,3,6)(2,4,8)(5,9,14)(7,11,17)(10,15,22)(12,18,26)(13,19,28)(16,23,33)
     (20,29,40)(21,30,42)(24,34,47)(25,35,49)(27,37,52)(31,43,59)(32,44,60)
     (36,50,51)(38,53,69)(39,54,71)(41,56,74)(45,61,79)(46,62,81)(48,64,84)
     (55,72,73)(57,75,94)(58,76,96)(63,82,83)(65,85,105)(66,86,107)(67,87,109)
     (68,88,111)(70,90,114)(77,97,122)(78,98,124)(80,100,127)(89,112,113)(91,
     115,142)(92,116,143)(93,117,145)(95,119,148)(99,125,126)(101,128,157)
     (102,129,159)(103,130,161)(104,131,163)(106,133,166)(108,135,169)(110,
     137,172)(118,146,147)(120,149,183)(121,150,185)(123,152,188)(132,164,165)
     (134,167,203)(136,170,171)(138,173,209)(139,174,211)(140,175,213)(141,
     176,215)(144,178,218)(151,186,187)(153,189,227)(154,190,229)(155,191,231)
     (156,192,232)(158,194,235)(160,196,238)(162,198,241)(168,204,246)(177,
     216,217)(179,219,261)(180,220,263)(181,221,265)(182,222,267)(184,223,268)
     (193,233,234)(195,236,281)(197,239,240)(199,242,287)(200,243,289)(201,
     244,291)(202,245,293)(205,247,296)(206,248,298)(207,249,299)(208,250,300)
     (210,252,303)(212,254,306)(214,256,309)(224,269,323)(225,270,324)(226,
     271,326)(228,273,329)(230,275,332)(237,282,337)(251,301,302)(253,304,357)
     (255,307,308)(257,310,363)(258,311,365)(259,312,367)(260,313,369)(262,
     315,372)(264,317,375)(266,319,378)(272,327,328)(274,330,388)(276,333,277)
     (278,334,393)(279,335,394)(280,336,396)(283,338,399)(284,339,401)(285,
     340,403)(286,341,404)(288,343,354)(290,295,349)(292,346,410)(294,348,413)
     (297,351,353)(305,358,417)(314,370,371)(316,373,431)(318,376,377)(320,
     379,436)(321,380,438)(322,381,440)(325,383,386)(331,389,446)(342,405,406)
     (344,407,350)(345,408,409)(347,411,463)(355,415,468)(356,416,470)(359,
     418,472)(360,419,474)(361,420,475)(362,421,477)(364,422,478)(366,424,481)
     (368,426,484)(374,432,489)(382,441,442)(384,443,499)(385,444,500)(387,
     445,502)(390,447,505)(391,448,507)(392,449,508)(395,452,512)(397,453,513)
     (398,430,488)(400,455,514)(402,457,517)(412,464,525)(414,466,528)(423,
     479,541)(425,482,483)(427,485,547)(428,486,549)(429,487,454)(433,490,551)
     (434,491,552)(435,492,553)(437,494,554)(439,496,557)(450,509,567)(451,
     510,511)(456,515,570)(458,518,493)(459,519,574)(460,520,576)(461,521,578)
     (462,522,579)(465,526,527)(467,529,584)(469,531,587)(471,532,588)(473,
     534,591)(476,537,595)(480,542,599)(495,555,556)(497,558,614)(498,559,501)
     (503,562,618)(504,563,620)(506,565,623)(516,571,627)(523,580,524)(530,
     585,586)(533,589,590)(535,592,643)(536,593,594)(538,596,646)(539,597,648)
     (540,598,650)(543,600,652)(544,601,654)(545,602,655)(546,603,657)(548,
     605,660)(550,607,640)(561,616,670)(564,621,622)(566,624,677)(568,625,679)
     (569,626,680)(572,628,683)(573,609,663)(575,630,686)(577,631,688)(581,
     634,692)(582,635,674)(583,636,687)(604,658,659)(606,661,678)(608,662,639)
     (610,664,713)(611,665,715)(612,666,716)(613,667,718)(615,668,719)(617,
     671,723)(619,673,726)(629,684,685)(632,689,734)(633,690,736)(637,649,702)
     (638,694,740)(641,695,741)(642,696,743)(644,697,744)(645,698,746)(647,
     700,747)(651,703,728)(653,705,752)(656,708,754)(669,720,699)(672,724,725)
     (675,710,755)(676,727,707)(681,730,766)(682,731,768)(691,735,771)(693,
     738,711)(701,748,749)(704,750,751)(706,753,783)(712,732,714)(717,758,787)
     (721,761,722)(729,764,791)(733,769,763)(737,773,774)(739,775,799)(742,
     777,759)(745,780,804)(756,785,807)(757,778,786)(760,788,782)(762,790,811)
     (765,792,814)(767,794,817)(770,797,798)(776,800,801)(779,802,803)(781,
     805,822)(789,810,824)(793,815,816)(795,818,830)(806,823,827)(809,821,832)
     (812,826,813)(819,825,834)(820,831,837)(828,835,838)(829,836,840);