Find and count a character in a cell

Hi everyone,

I have a question about calc functions. I've got a cell with the entire name of a person: Ex.: "Gabrielle Antoine Dugos Fermin".
And I need to count the number of times that the blankspace " " appears within the character string, say, 4 times. If I have a cell "John Camille Smith" I'd like to see a number 2, of 2 times.
What function is useful for this?

Please help.

I didn't find the right solution from the Internet.

References:
forum.openoffice.org/en/forum/viewtopic.php?f=9&t=42506
Business Overview Examples

Thanks