I am trying to write a code for the question, but I am unable to get the logic of the code. So can anyone write code to this question using python?

Question:

Mr. Vincent works in a doormat manufacturing company. One day, he designed a new doormat with the following specifications:

• Mat size must be N x M. ( N is an odd natural number, and M is 3 times of N .)
• The design should have ‘WELCOME’ written in the center.
• The design pattern should only use |, . and - characters.

Input:  7 21

output:

---------.|.---------

------.|..|..|.------

---.|..|..|..|..|.---

-------WELCOME-------

---.|..|..|..|..|.---

------.|..|..|.------

---------.|.---------