application_vnd.jupyter.stderr_output_1.png
"""
atom_list = []
for filename in os.listdir("../input/structures"):
    atom_list = atom_list + list(read_xyz(path, filename)['atom'])
atom_list = set(atom_list)
print(atom_list)
"""
print("{'O', 'H', 'C', 'F', 'N'}")