program read

      implicit none

      integer i, j, k, kx, ky, kz, n, repno
      parameter(n=1500)
      double precision x0, y0, z0
      double precision x1, y1, z1
      double precision x2, y2, z2
      double precision bz0, bz1, bz2
      double precision x(n), y(n), z(n), bx(n), by(n), bz(n), tmp
      double precision dr(8),rat(8),bzp(8), rattot, bzmrat, bzave
      integer xrep, yrep, zrep
      parameter(xrep=3)
      parameter(yrep=1)
      parameter(zrep=60)
      open(11,file='z.dat',status='old')

      i=1
 20   read(11,*,end=30) x(i), y(i), z(i), bx(i)
      if(x(i).eq.3.and.y(i).eq.2) write(14,*) x(i), y(i), z(i), bx(i)
      i=i+1
      goto 20
 30   tmp = 1
      return
      end