How to Create the Rules for This Password Structure

[rustyshackleford]

I am trying to carry out a dictionary attack for a password that is of this structure:

• 15 characters
  
  
• Lowercase letters and 0-9
  
  
• First a five letter word then 4 numbers, then 6 letter word
  

Examples of possible passwords:
creek8937basket
arrow3156hardly
eager4109eleven

How would I create the rules for this. I have a dictionary of the ~6000 english 5 letter words and top 10000 english 6 letter words. I could put those together into one dictionary but I am not sure how to make the rules for the above. Could someone help me?

 Thank you in advance!