I have two text files (FILE1.txt  & FILE2.txt) arranged in newlines. I want to combine the two lists so that the output text file (FILE3.txt) appear  as below:

FILE1.txt                                    FILE2.txt                [removed]                    apple                      [removed]                    orange                      [removed]                    mango                [removed][removed][removed][removed][removed][removed][removed][removed][removed] FILE1.txt & FILE2.txt  can have up to million lines. So a python  script can be written to combine the lists