Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_5228 ( "Season" text, "Tier" real, "League" text, "Pos." real, "Postseason" text, "European competitions" text )

### Question ###
What is the total number of tiers for the postseason of semifinalist?

### Accurate SQL ###

SELECT SUM("Tier") FROM table_5228 WHERE "Postseason" = 'semifinalist'