a21 := (1,2,4,7)(3,5,9,14)(6,10,16,24)(8,12,19,29)(11,17,26,39)(13,20,31,46)
     (15,22,34,51)(18,27,41,58)(21,32,48,67)(23,35)(25,37,53,73)(28,42,60,82)
     (30,44,62,84)(33,49,69,92)(36,52,71,96)(38,54,45,63)(40,56,77,104)(43,61,
     83,111)(47,65,88,117)(50,70,94,124)(55,75,101,79)(57,78,106,138)(59,80)
     (64,86)(66,89,81,108)(68,90)(72,97,128,163)(74,99)(76,102)(85,113,146,
     187)(87,115,149,191)(91,120)(93,122,156,200)(95,125,123,157)(98,129,165,
     211)(100,131,168,215)(103,134,172,219)(105,136,175,148)(107,139,145,186)
     (109,141,181,229)(110,142,137,176)(112,144,185,235)(114,147,189,239)(118,
     151,194,245)(119,152,155,198)(121,154,197,248)(126,160,204,255)(127,161,
     206,258)(130,166,213,265)(132,169,162,207)(133,170,217,269)(135,173,221,
     273)(140,179,227,281)(143,183,232,287)(150,192,243,301)(153,195,167,214)
     (158,190,240,297)(159,202,252,312)(164,209,261,321)(171,218,271,332)(174,
     222,275,337)(177,224)(178,225,278,342)(180,228)(182,230,284,348)(184,233,
     289,353)(188,237,293,359)(193,199,249,308)(196,247,305,373)(201,250,309,
     282)(203,253,314,381)(205,256,316,383)(208,260,319,388)(212,263,324,295)
     (216,267,329,400)(220,262,322,379)(223,276,339,411)(226,279)(231,285,349,
     422)(234,259)(236,291,356,430)(238,294,361,432)(241,298,363,434)(242,299,
     365,437)(244,302,368,439)(246,303,370,441)(251,310,320,389)(254,286)(257,
     317,385,399)(264,325,395,360)(266,327,350,423)(268,326,396,466)(270,330,
     402,421)(272,333,405,336)(274,335)(277,340,292,357)(280,344,416,484)(283,
     346,419,488)(288,351,425,495)(290,354,427,499)(296,358,375,447)(300,366,
     362,433)(304,371,443,512)(306,374,446,517)(311,378,451,521)(313,380,424,
     493)(315,382)(318,386)(323,392,463,530)(328,398,469,537)(331,403,472,541)
     (334,406,338,409)(341,413,481,550)(343,394,465,533)(345,417,486,555)(347,
     420,490,558)(352,426,497,564)(355,428,500,540)(364,435,506,570)(367,407,
     475,545)(369,440,511,576)(372,444,514,579)(376,448,518,582)(377,449,519,
     510)(384,455,504,560)(387,458,456,524)(390,460,528,591)(391,461,479,412)
     (393,464,450,520)(397,467,534,595)(401,459,527,589)(404,473,543,604)(408,
     476,546,429)(410,478,548,608)(414,482,551,516)(415,483,431,501)(436,507)
     (438,508,573,624)(442,452)(445,515,580,553)(453,522,584,632)(454,523,585,
     487)(457,525,587,502)(462,529,470,538)(468,535,597,642)(471,539,602,503)
     (474,498,565,563)(477,547)(480,549)(485,554,612,646)(489,557,615,567)
     (491,559,571,572)(496,562,617,606)(505,568,621,552)(509,574,625,661)(513,
     578)(526,588,596,641)(531,593,620,656)(532,594,640,670)(536,598,592,638)
     (542,603,647,673)(544,605,649,639)(556,614,654,679)(561,616,631,643)(566,
     619)(569,618)(575,590)(577,627,663,636)(581,628)(583,630,662,635)(586,
     633,667,607)(599,637,669,609)(600,644)(601,645,672,686)(610,651,676,688)
     (613,652)(622,658,653,678)(623,659,680,689)(626,655)(634,668,684,691)
     (650,675)(657,674,687,660)(664,666,682,677)(665,681)(671,685,683,690)
     (692,693);