('CID100013298', 2),Acetohydroxamicacid, N-(p-styrylphenyl)- (7CI,8CI)
('CID100013298', 2),Acetohydroxamicacid, N-(p-styrylphenyl)-, (E)- (8CI)
('CID100031071', 1),Acetohydroxamicacid, N-fluoren-3-yl- (8CI)
ldiff: defaultdict(<type 'list'>, {'CID100013298': [31, 33], 'CID100031071': [23]})
f1: [31, 33]
f2: [23]
c1: Counter({33: 1, 31: 1})
c2: Counter({23: 1})
The chosen was  ... CID100031071