Count number of commas in a cell

Hello,

I need an Excel function that looks into a cell and depending on its content, puts in a number in the cell to the right of it.  So the criteria is that if the cell is blank, returns 0 in the next column over, if the cell does not contain a comma in it, returns 1, if there is one comma in the cell, returns 2, if there are two commas in the cell, returns 3, and if there are three commas in the cell, then returns 4....  

For example

     col A                        col B would return the following number

1   MBA                            1

2   MD                              1

3   MBA,MD                     2

4   MBA,MD,Ph.D             3

5                                       0

6   Ph.D                            1

7                                       0

8  MD,Ph.D                       2

9  MBA,MD,MS,Ph.D        4

10 MS                              1

11 MBA,Ph.D,MS             3

Thank you for any assistance