sum the occurence of specified words (stored in array) in a string

Dear Forum,

I have the following issue: I would like to sum or count the occurences of specific words in a string (no case sensitive). In the example below column A contains the words that need to be found in cell B1. Here, the result would be 2 since the strings "Hello" and "Rum" are in the string "Hello_ExcelForum"; the string "Ghost" is not within B1 and the empy cell (A4) should neither not be counted. I tried the formula IF(SUMPRODUCT(--ISNUMBER(SEARCH(A1;B1)))>0=TRUE;1;0), which only works for the first cell in column A, however I cannot extend it to the whole Array A1:A4.

I really appreciate your halp and many thanks for your Support with this!

All the best,
mag2

	A	B
1	Hello	Hello_ExcelForum
2	Rum
3	Ghost
4

What would happen with B1 being "Hello Yellow" and the search word is "ello"? What should the answer be?