('CID103037768', 1),N-4-Azido-2-nitrophenyl-6-aminocaproicacid
('CID100096812', 1),Dinitrophenyl-e-aminocaproicacid
ldiff: defaultdict(<type 'list'>, {'CID103037768': [26], 'CID100096812': [16]})
f1: [26]
f2: [16]
c1: Counter({26: 1})
c2: Counter({16: 1})
The chosen was  ... CID100096812