Input: Article: In Greece Carnival is also known as the Apokriés (Greek: Αποκριές, "saying goodbye to meat"), or the season of the "Opening of the Triodion", so named after the liturgical book used by the church from then until Holy Week. One of the season's high points is Tsiknopempti, when celebrants enjoy roast beef dinners; the ritual is repeated the following Sunday. The following week, the last before Lent, is called Tyrinē (Greek: Τυρινή, "cheese [week]") because meat is forbidden, although dairy products are not. Lent begins on "Clean Monday", the day after "Cheese Sunday". Throughout the Carnival season, people disguise themselves as maskarádes ("masqueraders") and engage in pranks and revelry.

Now answer this question: What does the Opening of the Triodion derive from?

Output: the liturgical book used by the church

Input: Article: The Tito-Stalin split had large ramifications for countries outside the USSR and Yugoslavia. It has, for example, been given as one of the reasons for the Slánský trial in Czechoslovakia, in which 14 high-level Communist officials were purged, with 11 of them being executed. Stalin put pressure on Czechoslovakia to conduct purges in order to discourage the spread of the idea of a "national path to socialism," which Tito espoused.

Now answer this question: What country had pressure put on it by Stalin to conduct purges?

Output: Czechoslovakia

Input: Article: During the 18th and 19th centuries, federal law traditionally focused on areas where there was an express grant of power to the federal government in the federal Constitution, like the military, money, foreign relations (especially international treaties), tariffs, intellectual property (specifically patents and copyrights), and mail. Since the start of the 20th century, broad interpretations of the Commerce and Spending Clauses of the Constitution have enabled federal law to expand into areas like aviation, telecommunications, railroads, pharmaceuticals, antitrust, and trademarks. In some areas, like aviation and railroads, the federal government has developed a comprehensive scheme that preempts virtually all state law, while in others, like family law, a relatively small number of federal statutes (generally covering interstate and international situations) interacts with a much larger body of state law. In areas like antitrust, trademark, and employment law, there are powerful laws at both the federal and state levels that coexist with each other. In a handful of areas like insurance, Congress has enacted laws expressly refusing to regulate them as long as the states have laws regulating them (see, e.g., the McCarran-Ferguson Act).

Now answer this question: What is a law enacted by Congress that states that it refuses to regulate some industries as long as the states have regulations in place already?

Output:
McCarran-Ferguson Act