('CID100004735', 1),p,p'-(Pentamethylene-dioxy)bis-benzamidine
('CID100001499', 1),BIS-BENZAMIDINE
ldiff: defaultdict(<type 'list'>, {'CID100004735': [27], 'CID100001499': [0]})
f1: [27]
f2: [0]
c1: Counter({27: 1})
c2: Counter({0: 1})
The chosen was  ... CID100001499