module m_sort
contains
  subroutine sort(n,ra)

  dimension ra(n)
   
   l=n/2+1
   ir=n

10 continue
   if(l.gt.1)then
     l=l-1
     rra=ra(l)
     else
     rra=ra(ir)
     ra(ir)=ra(1)
     ir=ir-1
     if(ir.eq.1)then
      ra(1)=rra
      return
     endif
   endif

    i=l
    j=l+l
20  if(j.le.ir)then
     if(j.lt.ir)then
      if(ra(j).lt.ra(j+1))j=j+1
     endif
     if(rra.lt.ra(j))then
       ra(i)=ra(j)
       i=j
       j=j+j
       else
       j=ir+1
     endif
     go to 20
     endif

    ra(i)=rra
    go to 10
  end subroutine sort
end module m_sort