Given the task definition and input, reply with output. This task involves annotating the answer type to a given question that involve some kind of complex reasoning (including numerical reasoning). Note that the questions require looking at more than one part of the passage to answer. There are 3 possible answer types (i) spans, (ii) numbers and (iii) dates. If the answer can be found in the passage, label it as "span". If the answer is a number, label as "number". Similarly, label "date" if you think the answer to the given question is a date.

Passage: The Czech lands were among the first industrialized countries in continental Europe during the German Confederation era. The Czech industrial tradition dates back to the 19th century, when the Lands of the Bohemian Crown were the economic and industrial heartland of the Austrian Empire and later the Austrian side of Austria-Hungary. The Czech lands produced a majority of all industrial goods in the Empire, some of which were almost monopolistic. The Czechoslovak crown was introduced in April 1919. Introduced at a 1:1 ratio to the Austro-Hungarian currency, it became one of the most stable currencies in Europe. The First Republic became one of the 10 most developed countries of the world . The consequences of the 1938 Munich Agreement and subsequent occupation were disastrous for the economy. After the occupation and forced subordination of the economy to German economic interests, the crown was officially pegged to the mark at a ratio of 1:10, even though the unofficial exchange rate was 1 to 6-7 and Germans immediately started buying Czech goods in large quantities. In accordance with Stalin's development policy of planned interdependence, all the economies of the socialist countries were tightly linked to that of the Soviet Union. Czechoslovakia was the most prosperous country in the Eastern Bloc, however it continued to lag further behind the rest of the developed world. With the disintegration of the communist economic alliance in 1991, Czech manufacturers lost their traditional markets among former communist countries in the east. Today, this heritage is both an asset and a liability. The Czech Republic has a well-educated population and a well-developed infrastructure.
Question: How many years after the Czechoslovak crown was introduced was the Munich Agreement?
number