a21 := (1,3,6,11,19,32,53)(2,4,8,14,24,40,66)(5,9,16,27,45,74,118)(7,12,21,35,
     58,93,148)(10,17,29,48,79,126,199)(13,22,37,61,98,156,244)(15,25,42,69,
     110,175,272)(18,30,50,82,131,206,316)(20,33,55,89,142,223,339)(23,38,63,
     101,161,251,377)(26,43,71,113,180,280,413)(28,46,76,121,191,114,181)(31,
     51,84,134,210,320,465)(34,56,88,140,220,335,484)(36,59,95,151,237,358,
     326)(39,64,103,164,255,381,534)(41,67,107,170,264,393,549)(44,72,115,183,
     283,417,579)(47,77,123,194,299,437,607)(49,80,128,202,309,451,623)(52,85,
     136,213,324,470,648)(54,87,139,218,332,480,663)(57,91,145,228,345,495,
     252)(60,96,153,240,362,515,701)(62,99,158,247,371,527,712)(65,104,166,
     258,385,538,581)(68,108,172,267,398,553,737)(70,111,177,275,406,564,748)
     (73,116,185,286,420,583,227)(75,119,189,292,83,132,208)(78,124,196,302,
     441,612,795)(81,129,204,312,454,405,562)(86,137,215,327,473,652,759)(90,
     143,225,341,318,461,637)(92,146,230,348,498,677,864)(94,149,234,354,507,
     692,876)(97,154,105,167,260,387,467)(100,159,249,374,528,236,169)(102,
     162,253,379,531,716,738)(106,168,262,390,545,673,859)(109,173,269,376,
     530,715,895)(112,178,277,409,569,756,925)(117,186,288,423,587,769,935)
     (120,133,209,319,463,640,824)(122,192,296,432,602,786,224)(125,197,303,
     442,613,796,954)(127,200,307,287,421,585,768)(130,205,314,457,632,591,
     634)(135,211,322,468,644,160,250)(138,216,329,342,491,674,861)(141,221,
     193,297,434,603,544)(144,226,343,493,675,863,693)(147,231,350,501,684,
     869,554)(150,235,356,510,696,881,994)(152,238,313,455,629,813,609)(155,
     242,365,519,373,520,685)(157,245,369,524,708,889,808)(163,254,233,352,
     504,688,871)(165,256,383,452,624,263,391)(171,265,395,382,535,642,827)
     (174,270,401,557,536,721,846)(176,273,403,408,567,753,867)(179,278,295,
     431,600,783,949)(182,282,416,577,425,590,772)(184,284,419,582,764,933,
     1029)(187,289,424,589,770,695,879)(188,290,426,592,774,939,729)(190,293,
     430,598,782,947,1035)(195,300,439,610,792,953,1037)(198,304,444,614,797,
     691,874)(201,308,449,620,804,959,334)(203,310,453,626,448,241,363)(207,
     317,460,635,819,967,1048)(212,323,469,646,533,718,897)(214,325,472,651,
     835,758,916)(217,330,477,658,711,891,1008)(219,333,482,666,851,987,1011)
     (222,337,487,670,856,923,794)(229,346,496,679,862,428,595)(232,351,502,
     619,802,957,625)(239,360,402,558,503,686,870)(243,366,521,706,680,866,
     992)(246,370,464,641,826,773,893)(248,372,281,414,575,713,892)(257,384,
     500,683,506,690,873)(259,386,540,726,903,559,743)(261,388,542,509,662,
     848,985)(266,396,488,671,857,989,732)(268,399,555,739,914,301,440)(271,
     367,522,707,888,1005,1039)(274,404,561,744,807,960,1041)(276,407,566,751,
     906,977,315)(279,411,518,705,311,380,532)(285,361,513,698,347,497,616)
     (291,427,594,777,483,436,605)(294,344,494,676,678,865,492)(298,435,551,
     735,912,719,898)(305,445,615,593,775,940,338)(306,446,617,800,956,1001,
     942)(321,466,643,829,972,1052,842)(328,474,654,839,978,1055,1077)(331,
     478,660,845,983,622,650)(336,485,668,854,974,1045,943)(340,489,378,429,
     596,779,944)(349,499,682,868,917,833,975)(353,505,364,517,704,548,697)
     (355,508,694,878,995,611,793)(357,511,422,586,537,722,901)(359,375,529,
     714,894,1010,639)(368,471,649,834,930,924,725)(389,543,730,907,1016,1066,
     990)(392,547,669,855,433,539,724)(394,550,734,910,823,948,486)(397,514,
     699,883,1000,1059,560)(400,556,741,799,928,976,576)(410,570,541,727,904,
     844,982)(412,572,565,749,921,1024,1068)(415,573,736,438,608,791,952)(418,
     580,763,931,887,1004,915)(443,588,723,902,512,523,552)(447,618,604,788,
     665,850,687)(450,621,806,750,922,571,757)(456,630,815,964,1044,814,962)
     (458,574,475,655,841,980,1036)(459,633,818,584,766,785,659)(462,638,822,
     755,578,761,790)(476,656,843,825,971,1051,812)(479,661,847,798,955,1014,
     860)(481,664,849,986,984,563,746)(490,672,858,853,803,958,1040)(516,702,
     762,929,1026,938,546)(525,709,890,1007,1062,1054,809)(526,710,760,927,
     1025,645,821)(568,754,830,973,1023,1021,657)(597,780,945,1033,631,816,
     965)(599,720,899,1013,951,742,882)(601,784,913,1019,776,941,911)(606,628,
     811,817,966,1047,961)(627,810,765,840,979,1056,1064)(636,820,969,1050,
     1034,1042,789)(647,832,747,920,1022,1018,681)(653,837,740,880,999,1030,
     836)(667,852,988,1057,1061,998,801)(689,872,717,896,731,908,1017)(700,
     884,1002,981,1012,937,828)(703,886,932,1028,1069,1078,1032)(728,905,1015,
     1065,1031,1070,1058)(733,909,900,745,918,752,805)(767,934,771,936,926,
     970,1027)(781,946,919,1020,1009,1053,1006)(787,950,1038,1067,1046,1063,
     831)(875,996,963,1043,1073,1074,1080)(877,997,885,1003,1060,993,991)(968,
     1049,1075,1071,1079,1076,1072);