('CID100301122', 2),Z-D-homoserinelactone
('CID100301122', 2),Z-L-homoserinelactone
('CID100135011', 1),Z-L-homoserinelactone
ldiff: defaultdict(<type 'list'>, {'CID100135011': [4], 'CID100301122': [4, 4]})
f1: [4, 4]
f2: [4]
c1: Counter({4: 2})
c2: Counter({4: 1})
The chosen was ... CID100301122