('CID100241448', 1), Succinicacid, methylene-, dihydrazide (7CI,8CI)
('CID124846228', 1),Succinicacid, 1-methyl-2-propynyl ester (6CI)
ldiff: defaultdict(<type 'list'>, {'CID100241448': [36], 'CID124846228': [33]})
f1: [36]
f2: [33]
c1: Counter({36: 1})
c2: Counter({33: 1})
The chosen was  ... CID124846228