Combining several columns to one in a huge pivot

I haved search and searched for a working solution for this but I cant seem to get it to work.
Im attaching a very slimmed down version of what I am trying to create.

We are trying to put together a lot of statistics from our visits to the company. These are filled in in a table where we note lots of different statistics. As many different people use the same file (for adding info about their visit) we are using data verify for creating drop down lists. Sometimes the visit is for two different apartments (or even three) or there are two different guides welcoming the visit. Therefor we have several columns. The problem arises when we need to combine the information, for instans, see which deparments have had how many visits and so on. All "deparment columns" then needs to be combined into one field.
I thought this would work with a calculated field (dep1+dep2+dep3) but I keep getting zerovalues.

Could somebody please help me out here?

Thank you and sorry for my late reply.
I need to combine all columns of departments (Departments visited/ More visited departments/ Welcoming department/ Other departments involved/ Extra field for more deparments/) into one pivot-field: "Departments" for so knowing how many times each department has been involved in the visits.
Also, the departments are usually based on a list, but two of the columns allow free values (as the list includes the most common apartments but not all) so I cant on forehand tell what values to expect.
I've tried solving this with a manual formula based table combining an Advanced Filter for unique values + Count.If formula but it keeps returning double values as the same apartments appears in all columns. Any way to solve this without onto that adding another pivottable? All of this should be easy enough to handle for my users....

So thankful for your quick reply.
However, there isnt a masterlist of the departments, two of the columns allows free values, so there isnt a way on forehand tell what values to expect. Hence my try for a solution using the Advanced Filter/Unique values...