[Tutor] How to create a dictionary for ount elements

[jarod_v6 at libero.it]

Dear all thanks for your suggestion!!!
Thanks to your suggestion I create this structure:with open("prova.csv") as p:
    for i in p:
        lines =i.rstrip("\n").split("\t")
   ...:         print lines
   ...:         
['programs ', 'sample', 'gene', 'values']
['program1', 'sample1', 'TP53', '2']
['program1', 'sample1', 'TP53', '3']
['program1', 'sample2', 'PRNP', '4']
['program1', 'sample2', 'ATF3', '3']
['program2', 'sample1', 'TP53', '2']
['program2', 'sample1', 'PRNP', '5']
['program2', 'sample2', 'TRIM32', '4']
['program2', 'sample2', 'TLK1', '4']

In [4]: with open("prova.csv") as p:
    for i in p:
        lines =i.rstrip("\n").split("\t")
        dizlines
diz

In [4]: with open("prova.csv") as p:
    for i in p:
        lines =i.rstrip("\n").split("\t")
        line = (lines[0],lines[1])
   ...:         diz.setdefault(line,set()).add(lines[2])
   ...:         

In [5]: diz
Out[5]: 
{('program1', 'sample1'): {'TP53'},
 ('program1', 'sample2'): {'ATF3', 'PRNP'},
 ('program2', 'sample1'): {'PRNP', 'TP53'},
 ('program2', 'sample2'): {'TLK1', 'TRIM32'},
 ('programs ', 'sample'): {'gene'}}


So what I want to do is to use intersect between the keys recursively:
s = diz[('program2', 'sample1']
   ....: 
   ....: 
KeyboardInterrupt

In [14]: s = diz[('program2', 'sample1')]

In [15]: s
Out[15]: {'PRNP', 'TP53'}

In [16]: a
Out[16]: {'ATF3', 'PRNP'}

In [17]: s.inte
s.intersection         s.intersection_update  

In [17]: s.intersection(a)
Out[17]: {'PRNP'}

How can Have a intersect of all my dictionary and from ('program1', 'sample1') 
vs ('program1', 'sample2')...
I want to count  how many genes are common
Thanks in advance  for your help!