Counting text strings with variations

[JXHK_22]

I would like to count the occurrence of the text string "ama" within a column, e.g. 

=COUNTIF(A1:A6000),"*ama*")

However, I would also like to count other variations: amas, ama's, AMA, AMAs, AMA's

without capturing text like "Amanda" that features the string "ama". 

Appreciate advice on how to approach this!

[#2]

without capturing text like "Amanda" that features the string "ama". on my side it works

[#3]

Hi there. Thanks for your help, but not sure that I understand. I mean that I would like to count all variations as a standalone string (ama, amas, ama's, AMA, AMAs, AMA's) but not any instances where the string appears within another word such as Amanda.

[#4]

please，
Attach a sample excel file to your post. Show input and desired output.