Ex5


write a programm which generate a .txt file by shuffeling two txt file.
That is: if the generated file is named A.txt and the two files are B.txt and C.txt, 
then 
the first line of A.txt is the first line of B.txt,
the second line of A.txt is the first line of B.txt,
the third line of A.txt is the second line of B.txt,
the fourth line of A.txt is the second line of B.txt,
and so on