Adding Comma's to Strings in Excel 2016

I am trying to create a formula to add a comma after the 2nd string if there are more name than two and otherwise add a comma after first string.
But my formula is just adding the comma after first string.

My formula:

=SUBSTITUTE(A2," ",", ",1)

My strings:

Strings

ARISMEL SANTOS ROSARIO
ADREMIR J GAMBOA ORTIZ
  LOGAN NOVA HERNANDEZ MEJIA LACAYO
    ADREMIR J HERNANDEZ MEJIA
   AVERY GRAN

My unwanted result is:

ARISMEL, SANTOS ROSARIO
ADREMIR J, GAMBOA ORTIZ
LOGAN NOVA, HERNANDEZ MEJIA LACAYO
ADREMIR J, HERNANDEZ MEJIA
AVERY, GRANT

Solution

Assuming cell A1 has any of the example name you provided.

Put the following formula in B1 -> =LEN(A1) - LEN(SUBSTITUTE(TRIM(A1), " ", "")) and the formula in C1 -> =SUBSTITUTE(TRIM(A1)," ",", ",IF(B1<=2,1,2))

It is good to have trimmed text (which I have done in formula) to begin with.

See if this helps.

Edit: If you want to do it in a single formula, =SUBSTITUTE(TRIM(A1)," ",", ",IF((LEN(A1) - LEN(SUBSTITUTE(TRIM(A1), " ", ""))) <=2,1,2))