2π2 . b_while ( (2π1,(+.(2π1.2π2,1)o,(+)*.zip2.(select.(2π2.2π2,iota.2π2.2π1)o,select.(2π1.2π1,(mod)*.zip2.((+)*.zip2.(iota.2π2.2π1,repeat.(2π1.2π2,2π2.2π1)o)o,repeat.(id,id)o.2π2.2π1)o)o)o)o)o , < . (2π1.2π2,2π2.2π1)o ) . ((id,#)o,(1,id)o)o