user: You are given a paragraph, with numbered sentences, and a question. Write the numbers of the sentences needed to answer the given question. Separate multiple sentence numbers with a comma (", "). E.g. "1, 2" would be the correct response if Sent 1 and Sent 2 are needed to answer the given question (do not include sentences that contain no information that is necessary to answer the question). Sort the sentence numbers in an increasing order (i.e., '1, 2', instead of '2, 1'). Your answer should not contain anything than the sentence numbers separated by a comma (e.g. '1, 2, 3, 4'). The given question requires more than one sentence to answer. So, your answer must contain at least one comma (", ").
One example: Paragraph- Sent 1: A Republican bid to keep the government open past Friday includes no new money for the construction of a border wall along the U.S.-Mexico border, according to several congressional aides familiar with ongoing talks.
Sent 2: GOP leaders submitted the new offer Tuesday afternoon in an effort to appease Democrats, whose votes are needed to avert a shutdown of federal agencies, several House and Senate aides said.
Sent 3: However, Republicans also insisted on increases in border security and defense spending, including money to repair existing fencing and new surveillance technology to patrol the nearly 2,000-mile border.
Sent 4: Democrats have indicated that they would support such appropriations so long as no money goes toward an actual wall.
Question: Who has to be appeased to keep the government open?.
Solution is here: 1, 2.
Explanation: The question is: Who has to be appeased to keep the government open? The phrase "appease Democrats" is mentioned in Sent 2, about accepting offer that is mentioned in Sent 1 to "keep the government open". So, Sent 1 and Sent 2 are the sentences needed to answer this question.

Now, solve this: Paragraph- Sent 1: Alexander III of Macedon (20/21 July 356 - 10/11 June 323 BC), commonly known as Alexander the Great (Greek: Alexandros o Megas, Alexandros ho Megas [a.lek.san.dros ho me.gas]), was a King (Basileus) of the Ancient Greek kingdom of Macedon and a member of the Argead dynasty.
Sent 2: Born in Pella in 356 BC, Alexander succeeded his father, Philip II, to the throne at the age of twenty.
Sent 3: He spent most of his ruling years on an unprecedented military campaign through Asia and northeast Africa, until by the age of thirty he had created one of the largest empires of the ancient world, stretching from Greece to Egypt and into northwest India.
Sent 4: He was undefeated in battle and is considered one of history's most successful military commanders.
Sent 5: During his youth, Alexander was tutored by the philosopher Aristotle until the age of 16.
Sent 6: After Philip was assassinated in 336 BC, Alexander succeeded his father to the throne and inherited a strong kingdom and an experienced army.
Sent 7: He had been awarded the generalship of Greece and used this authority to launch his father's Panhellenic project to lead the Greeks in the conquest of Persia.
Sent 8: In 334 BC, he invaded the Achaemenid Empire, ruled Asia Minor, and began a series of campaigns that lasted ten years.
Sent 9: Alexander broke the power of Persia in a series of decisive battles, most notably the battles of Issus and Gaugamela.
Sent 10: He subsequently overthrew the Persian King Darius III and conquered the Achaemenid Empire in its entirety.
Sent 11: At that point, his empire stretched from the Adriatic Sea to the Indus River.
Sent 12: Seeking to reach the "ends of the world and the Great Outer Sea", he invaded India in 326 BC, but was eventually forced to turn back at the demand of his troops.
Sent 13: Alexander died in Babylon in 323 BC, the city he planned to establish as his capital, without executing a series of planned campaigns that would have begun with an invasion of Arabia.
Sent 14: In the years following his death, a series of civil wars tore his empire apart, resulting in several states ruled by the Diadochi, Alexander's surviving generals and heirs.
Sent 15: Alexander's legacy includes the cultural diffusion his conquests engendered, such as Greco-Buddhism.
Sent 16: He founded some twenty cities that bore his name, most notably Alexandria in Egypt.
Sent 17: Alexander's settlement of Greek colonists and the resulting spread of Greek culture in the east resulted in a new Hellenistic civilization, aspects of which were still evident in the traditions of the Byzantine Empire in the mid-15th century and the presence of Greek speakers in central and far eastern Anatolia until the 1920s.
Sent 18: Alexander became legendary as a classical hero in the mold of Achilles, and he features prominently in the history and myth of Greek and non-Greek cultures. 
Question: How long after Phillip's death did Alexander invade India?.
Solution:

assistant: 2, 6.