Need help combinding 2 different dictionaries

[IloveStuff]

I have to seperate dictionaries that im trying to combine but in between i want to have the numbers 0-9999 so
text1.txt 0001 text2.txt
text1.txt 0002 text2.txt
text1.txt 0003 text2.txt
....
text1.txt 9999 text2.txt
etc.
I tried this guide https://pthree.org/2013/04/22/password-a...on-attack/ but ended with the wrong results as I recieved ex:
Dog0001Cat
Dog0002Fish
instead of (which is what i wanted)
Dog0001Cat
Dog0002Cat
Dog0003Cat
......
Dog9999Cat

Im new to this so please be easy on me.