('CID106330306', 1),SELENOINOSINE
('CID100298363', 1),Se-(p-Nitrobenzyl)-6-selenoinosine
ldiff: defaultdict(<type 'list'>, {'CID100298363': [21], 'CID106330306': [0]})
f1: [0]
f2: [21]
c1: Counter({0: 1})
c2: Counter({21: 1})
The chosen was ... CID106330306