Here's a short story:

Siberia is an extensive geographical region, and by the broadest definition is also known as North Asia. Siberia has historically been a part of Russia since the 17th century. 

The territory of Siberia extends eastwards from the Ural Mountains to the watershed between the Pacific and Arctic drainage basins. The Yenisei River conditionally divides Siberia into two parts, Western and Eastern. Siberia stretches southwards from the Arctic Ocean to the hills of north-central Kazakhstan and to the national borders of Mongolia and China. With an area of , Siberia accounts for 77% of Russia's land area, but it is home to just 40 million people—27% of the country's population. This is equivalent to an average population density of about (approximately equal to that of Australia), making Siberia one of the most sparsely populated regions on Earth. If it were a country by itself, it would still be the largest country in area, but in population it would be the world's 35th-largest and Asia's 14th-largest. 

Worldwide, Siberia is well known primarily for its long harsh winters, with a January average of −25 °C (−13 °F), as well as its extensive history of use by Russian and Soviet administrations as a place for prisons, labor camps, and exile. (End of story)

Provide your best guess for the following question. Give ONLY the guess, no other words or explanation.

For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>

Here are a few examples of questions and answers:

Question: How cold is it in Jan?
Guess: average of −25 °C

Question: Is this a small area?
Guess: No

Now answer the following question in the same format.

Question: What is the eastern boundart?

Pacific and Arctic drainage basins