('CID100223146', 2),Phenyl para-toluenesulfonate
('CID100223146', 2),Phenyl Para-toluenesulfonate
('CID100006101', 2),para-toluenesulfonic acid
('CID100006101', 2),para-toluenesulfonate
ldiff: defaultdict(<type 'list'>, {'CID100223146': [7, 7], 'CID100006101': [4, 0]})
f1: [7, 7]
f2: [4, 0]
c1: Counter({7: 2})
c2: Counter({0: 1, 4: 1})
The chosen was  ... CID100006101