i need a formula that will look at a text/number in a column and go down the
column and add 1 to get a total number of items meeting the criteria.

example
column D
1, 2P
1P, 2, 3
1, 2
2
1P

how do i get it to search for a 1 in the string of text in column D and give
me the answer of 4 for the number of times it shows up in that column?
Thanks.