I am attempting to create a function to do the following.

I have to columns of data that I need to go through. I am attempting to
talley the number of occurences of each item.

To do this I need to go through column 'a' and every time it is 1, i then
must check column 'b'. If in column b the numbers 1,3,5,6 are found then I
need to add one to the talley. Can anyone suggest a way to do this. I
attempted to use countif formula but could not get something on it to work.