('CID100072355', 2),N-(N-(N2-(((1-Carboxy-2-phenylethyl)amino)carbonyl)-L-arginyl)-L-valyl)-D-phenylalanine, aldehyde deriv.
('CID100072355', 2),N-[N-[N2-[[(1-Carboxy-2-phenylethyl)amino]carbonyl]-L-arginyl]-L-valyl]-D-phenylalanine, aldehyde deriv.
('CID100446054', 2),D-[(AMINO)CARBONYL]PHENYLALANINE
('CID100446054', 2),D-[(AMINO)CARBONYL]PHENYLALANINE
ldiff: defaultdict(<type 'list'>, {'CID100072355': [72, 72], 'CID100446054': [0, 0]})
f1: [72, 72]
f2: [0, 0]
c1: Counter({72: 2})
c2: Counter({0: 2})
The chosen was  ... CID100446054