('CID100007121', 1),Mandelicacid, m-methoxy- (6CI,7CI,8CI)
('CID100111010', 1),Mandelicacid, p-fluoro-, ethyl ester (7CI,8CI)
ldiff: defaultdict(<type 'list'>, {'CID100007121': [22], 'CID100111010': [30]})
f1: [22]
f2: [30]
c1: Counter({22: 1})
c2: Counter({30: 1})
The chosen was ... CID100007121