('CID100069397', 1),Stearicacid, isopentyl ester (8CI)
('CID100111278', 1),Stearicacid, a-methyl- (4CI)
ldiff: defaultdict(<type 'list'>, {'CID100069397': [23], 'CID100111278': [17]})
f1: [23]
f2: [17]
c1: Counter({23: 1})
c2: Counter({17: 1})
The chosen was  ... CID100111278