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: What SI unit (International System of Units) of measurement is defined as The amount of substance that contains an equal number of elementary entities as there are atoms in 0.012kg of the isotope carbon-12?

Output: amount of substance, international system of units