extracting data from a list in a file

[clarablanes]

good morning guys,

I am trying to extract the descriptor in bold in a list (the list is in a file):

This is the content of the file: training_set_sub.txt
[['Verapamil', 'COC1=C(OC)C=C(CCN©CCCC(C#N)(C©C)C2=CC(OC)=C(OC)C=C2)C=C1', 0, 71, '0', '13', '2', 6, 7.0, 0.46, 5.09, '1', '0.60', '5.888', -2.447620829090909, '-7.093', '0'], ['Norverapamil', 'COC1=CC=C(CCNCCCC(C#N)(C©C)C2=CC(OC)=C(OC)C=C2)C=C1OC', 0, 68, '1', '13', '2', 6, 7.0, 0.46, 5.14, '1', '3.06', '5.914', -3.918865, '-7.435', '0']]

What I am doing is:

file = open('training_set_sub.txt','r')
all = file.read().replace("'",'').split('], [')
b = str(all).split(',')
print (b)

for row in all:
    print (b[3])

but this way I obtain:
71
71
and I need to obtain
71
68

Could you help me, please?