from frowns import MDL
from frowns import Smiles
from string import *
import sys

if __name__ == '__main__':
    "Canonical Smiles Generator"

    if len(sys.argv) !=2:
        print "Usage: cansmiles xxx.sdf > xxx.smi"
        sys.exit(1)

    mdlfile = sys.argv[1]
   
    mol_info = MDL.sdin(open(mdlfile))
        
    while 1:
        try:
            mol, err, sdf_text = mol_info.next()
        except StopIteration:
            break
        print mol.cansmiles()