('CID100000867', 4),Malonicacid
('CID100000867', 4),Malonicacid, sodium salt (8CI)
('CID100000867', 4),Malonicacid, ion(2-) (8CI)
('CID100000867', 4),Malonicacid, disodium salt, monohydrate (8CI)
('CID100538366', 2),Malonicacid, methyl ester (6CI)
('CID100538366', 2),Malonicacid, dimethyl ester (6CI,8CI)
ldiff: defaultdict(<type 'list'>, {'CID100000867': [0, 19, 15, 34], 'CID100538366': [20, 26]})
f1: [0, 19, 15, 34]
f2: [20, 26]
c1: Counter({0: 1, 34: 1, 19: 1, 15: 1})
c2: Counter({26: 1, 20: 1})
The chosen was ... CID100000867