[L3] "EXACTLY" seems ambiguous... Hints please?

[Sejin Kim]

"surrounded by EXACTLY three big bodyguards on each of its sides" seems very ambiguous...

Not sure which case of the following counts:

[any text segment] --> URL

1. aBBBcDDDe --> BBBcDDD

2. aBCDeFGHi --> BCDeFGH

3. aBBBcDDDeFFFgHHHi --> BBBcDDDeFFFgHHH

4. aBCDeFGHiJKLmNOPq --> BCDeFGHiJKLmNOP

I get that 1 would most definitely be true... However I can't find But are the other cases good too?

Also are there any good resources for regex? Thanks :)