Reading from file containing integer and character

Question

I have a file like that:

5

a,b,c,d,e

a,b

b,c

d,e

a,c

e,e

3

1,2,3

1,2

2,1

3,3

10

a,b,c,d,e

a,a

b,b

c,c

d,d

e,e

a,b

b,a

c,a

d,a

e,a