Input: Article: In the second half of '90s, MP3 files began to spread on the Internet. The popularity of MP3s began to rise rapidly with the advent of Nullsoft's audio player Winamp, released in 1997. In 1998, the first portable solid state digital audio player MPMan, developed by SaeHan Information Systems which is headquartered in Seoul, South Korea, was released and the Rio PMP300 was sold afterwards in 1998, despite legal suppression efforts by the RIAA.

Now answer this question: In which country was the first portable audio player developed?

Output: South Korea

Input: Article: In 1983, the International Telecommunication Union's radio telecommunications sector (ITU-R) set up a working party (IWP11/6) with the aim of setting a single international HDTV standard. One of the thornier issues concerned a suitable frame/field refresh rate, the world already having split into two camps, 25/50 Hz and 30/60 Hz, largely due to the differences in mains frequency. The IWP11/6 working party considered many views and throughout the 1980s served to encourage development in a number of video digital processing areas, not least conversion between the two main frame/field rates using motion vectors, which led to further developments in other areas. While a comprehensive HDTV standard was not in the end established, agreement on the aspect ratio was achieved.

Now answer this question: What was used as a conversion between the two main frame/field rates?

Output: motion vectors

Input: Article: The history of Jews in Greece goes back to at least the Archaic Era of Greece, when the classical culture of Greece was undergoing a process of formalization after the Greek Dark Age. The Greek historian Herodotus knew of the Jews, whom he called "Palestinian Syrians", and listed them among the levied naval forces in service of the invading Persians. While Jewish monotheism was not deeply affected by Greek Polytheism, the Greek way of living was attractive for many wealthier Jews. The Synagogue in the Agora of Athens is dated to the period between 267 and 396 CE. The Stobi Synagogue in Macedonia, was built on the ruins of a more ancient synagogue in the 4th century, while later in the 5th century, the synagogue was transformed into Christian basilica.

Now answer this question: The history of Jews in Greece goes back to which era?

Output:
Archaic Era of Greece