def 1 1 hotpo  { k --  k 1 and if   k k + k + 1 +  else  k 1 >>  then } ;def 2 1 hotpo-loop  { k p --  k 1 = if              p            else              k hotpo  p 1 +  hotpo-loop            then } ;def 1 1 hotpo-period   0 hotpo-loop ;def 3 1 longest-loop  { k best best-period --    k 1 = if      best    else      k hotpo-period      { k-period --	k 1 -  k-period best-period < if best best-period 				    else k    k-period    then longest-loop }    then } ;def 1 1 longest   1 0 longest-loop ;