<|im_start|>system
Please reason step by step, and put your final answer within \boxed{}.<|im_end|>
<|im_start|>user
Given the following CIF representation:
data_CaBr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.91
_cell_length_b   5.91
_cell_length_c   6.87
_cell_angle_alpha   111.08
_cell_angle_beta   111.08
_cell_angle_gamma   37.72
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaBr
_chemical_formula_sum   'Ca2 Br2'
_cell_volume   135.84
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ca  Ca2  1  0.14  0.0  0.55  1.0
  Ca  Ca3  1  0.44  0.0  0.81  1.0
  Br  Br0  1  0.41  0.0  0.39  1.0
  Br  Br1  1  0.17  0.0  0.96  1.0

What is the crystal system of this material?<|im_end|>
<|im_start|>assistant
Given the following CIF representation:
data_CaBr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.91
_cell_length_b   5.91
_cell_length_c   6.87
_cell_angle_alpha   111.08
_cell_angle_beta   111.08
_cell_angle_gamma   37.72
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaBr
_chemical_formula_sum   'Ca2 Br2'
_cell_volume   135.84
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ca  Ca2  1  0.14  0.0  0.55  1.0
  Ca  Ca3  1  0.44  0.0  0.81  1.0
  Br  Br0  1  0.41  0.0  0.39  1.0
  Br  Br1  1  0.17  0.0  0.96  1.0

What is the crystal system of this material?