b21 := (1,3,6,8)(2,4)(5,7,10,12)(9,11,14,18)(13,16,21,27)(15,19,25,33)(17,22,
     29,28)(20,26,35,45)(23,30,39,34)(24,31,41,43)(32,42,50,60)(36,38,47,56)
     (37,46,54,65)(40,48,58,55)(44,51,62,71)(49,59,68,77)(52,63,73,83)(53,64,
     75,85)(57,66,70,81)(61,69,80,89)(67,78,79,88)(72,82,76,86)(74,84,92,98)
     (90,95,102,113)(91,96,104,114)(93,99,108,119)(94,100,110,122)(97,105,116,
     128)(101,111,124,106)(107,117,130,143)(109,120,133,146)(112,125,127,140)
     (115,126,139,150)(121,123,135,136)(129,141,151,158)(131,144,153,159)(132,
     145,154,160)(134,147,137,148)(138,149,156,162)(142,152,155,161)(157,163,
     165,164);