integer*2 nums(49)
      character*30 title, filename
      write (*,'(A\)') ' Name of data file:'
      read (*,'(A)') filename
      open (1,file=filename)
      read (1,'(A)') TITLE
      max=0
      do i=1,1000
      read (1,'(1x,49(I4,3x))',end=1) (NUMS(J),j=1,49)
      do j=1,48
      if (NUMS(J).gt.0.and.NUMS(J+1).gt.0) THEN
      if (max.lt.nums(j)) max=nums(j)
      if (max.lt.nums(j+1)) max=nums(j+1)
      endif
      enddo
      enddo
1     close (1)
      open (1,file=filename)
      open (2,file='sea.net')
      write (2,'(A,3i4)') '*Vertices', max
      do i=1,max
      write (2,'(3i4)') i
      enddo
      write (2,'(A,3i4)') '*Arcs'
      ii=i-1
      open (1,file=filename)
      read (1,'(A)') TITLE
      do i=1,ii
      read (1,'(1x,49(I4,3x))',end=2) (NUMS(J),j=1,49)
      do j=1,48
      if (NUMS(J).gt.0.and.NUMS(J+1).gt.0) THEN
      write (2,'(3i4)') nums(j), nums(j+1), 1
      endif
      if (NUMS(J).gt.0.and.NUMS(J+1).lt.0) THEN
      write (2,'(3i4)') nums(j), -nums(j+1), 2
      endif
      if (NUMS(J).lt.0.and.NUMS(J+1).gt.0) THEN
      write (2,'(3i4)') -nums(j), nums(j+1), 3
      endif
      if (NUMS(J).lt.0.and.NUMS(J+1).lt.0) THEN
      write (2,'(3i4)') -nums(j+1), -nums(j), 1
      endif
      enddo
      enddo
2     end
CENTAILMENT CHAINS: 10%
C2345444412344441234444123
C  11 >>  29 >>  26 >>   8 >>  35 >>  23 >>  28 >>  31 >>   1
C  16 >>  18 >>  15 >>  14 >>  13 >>  31
C   7 >>   4 >>  32 >>  31
C  24 >>  25 >>  30 >>  27 >>  31