Formula for counting text values in column when value is repeated in cells

In the uploaded workbook I have 2 active sheets. Sheet1 and Calling Sheet.

In "Calling sheet" Column Y lists the results of calling activity.

On "Sheet1" there are 4 cells B1:B4 I need a formula that will count the initials of the staff members in the notes in they column y cells in the "Calling Sheet". So Mark Weaver is MW, Jim Saunders is JS....

I need a formula that will count the amount of times the initials of the listed people appear in the notes in column y. Bear in mind that in each cell the initials can be entered multiple times on new "Alt&Enter" lines.

So in conclusion I really need some help here!!