program myrft
      character*80 infile
      real fin(65536),fout(65536)
      real t,z1,z2,z3,z4
      real dt
      integer i
      common /FWORK/W(350000)
      print *, 'enter name of the input file'
      read(5,'(A80)') infile
      print *, 'opening input file ',infile
      open(unit=1,file=infile,status='old')
      do i=1,65536
        read(1,*) t,z1,z2,z3,z4
        fin(i) = (z3-z2)/(z3+z2)
        fout(i) = fin(i)
      enddo
      dt = t/65536
      close(unit=1)
      call rft(16,fin,1,fout,1,1)
      open(unit=1,file='myrft.out',status='new')
      do i=1,32768
        write(1,*) i/dt/65536,fout(i),fout(i+32768)
      enddo
      close(unit=1)
      end