Atom style in data file differs from currently defined atom style

Dear All,
I have the following error when I run my simulation:

LAMMPS (16 Feb 2016)
Reading data file …
orthogonal box = (-100 -100 -100) to (100 100 100)
2 by 2 by 5 MPI processor grid
WARNING: Atom style in data file differs from currently defined atom style (…/read_data.cpp:405)
reading atoms …
ERROR: Incorrect atom format in data file (…/atom.cpp:817)

here is part of my input file :

read_data 1st-unload.data

pair_style reax/c NULL checkqeq yes
pair_coeff * * ffield_PtNiCHO_2016.reax C H
neighbor 2.0 bin #2 because the default parameter for skin is 2 in real units
neigh_modify every 1 delay 0 check yes

fix charge all qeq/reax 1 0.0 10.0 1e-6 reax/c
timestep 0.2
reset_timestep 0

and here is my data file :

LAMMPS data file written by OVITO

17044 atoms
2 atom types
-100 100 xlo xhi
-100 100 ylo yhi
-100 100 zlo zhi

Masses

1 12.0 # C
2 1.08 # H

Atoms # full

1 0 1 0 -11.5424004 -26.1483994 -30.7555008
2 0 1 0 -7.1915102 -26.3794994 -31.5349007
3 0 2 0 -7.06429 -27.4570008 -31.4155998
4 0 1 0 -8.1540899 -25.6406002 -31.8355007
5 0 1 0 -6.1396899 -25.3069992 -31.3638001
6 0 1 0 -4.87103 -25.5198994 -30.5102997
7 0 1 0 -13.5418997 -24.1296997 -30.1130009
8 0 1 0 -12.5847998 -21.3649998 -30.8146

I have not defined any atom_style in my input code.
Thanks

https://lammps.sandia.gov/doc/atom_style.html

Default atom_style is atomic, while you have the data file in full
atom_style format.
Please include the atom_style appropriately.

Regards,

santhosh.