Definition: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

Positive Example 1 -
Input: Who was the first American President?
Output: president of the united states

Positive Example 2 -
Input: The Dutch duo of Ray Slijngaard and Anita Dels, who had 8 top ten hits in the 90s, were better known by what name?
Output: anita doth

Negative Example 1 -
Input: Anna Smashnova played which sport professionally until 2007?
Output: sport

Negative Example 2 -
Input: Rob Davis, Les Gray, Dave Mount and Ray Stiles are members of which pop group?
Output: david

Now complete the following example -
Input: The Belgian Revolution, that began after a performance at the Brussels opera in 1830, led to the secession of the Southern provinces of which kingdom to establish an independent Kingdom of Belgium?

Output: belgian revolution