def is_valid_input(ext):
	""" Checks if input file format is compatible with Open Babel """
	formats = ["dat", "ent", "fa", "fasta", "gro", "inp", "log", "mcif", "mdl", "mmcif", "mol", "mol2", "pdb", "pdbqt", "png", "sdf", "smi", "smiles", "txt", "xml", "xtc"]
	return ext in formats