Instructions: This task involves creating answers to complex questions, from a given passage. Answering these questions, typically involve understanding multiple sentences. Make sure that your answer has the same type as the "answer type" mentioned in input. The provided "answer type" can be of any of the following types: "span", "date", "number". A "span" answer is a continuous phrase taken directly from the passage or question. You can directly copy-paste the text from the passage or the question for span type answers. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words. A "number" type answer can include a digit specifying an actual value. For "date" type answers, use DD MM YYYY format e.g. 11 Jan 1992. If full date is not available in the passage you can write partial date such as 1992 or Jan 1992. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words.
Input: Passage: In the 1650s, Burma became entangled in the dynastic changes in China. In 1651, Ming armies fleeing from the Qing forces entered Kengyun , which had paid tribute to both China and Burma. King Pindale sent five regiments to the front in October 1651. But the armies were driven back by the Ming in December 1651. Pindale would not contest again. In 1658, Zhu Youlang, one of the sons of the last Ming emperor, and his 700 followers were given permission to stay at Sagaing. In early 1659, other fleeing Ming armies entered the Shan states, and occupied Nyaungshwe and Mone with the intention to set up a kingdom for their emperor. For the next two years, the Ming forces proved a menace to Upper Burma. Not only Pindale could not drive out the Ming but it was the Ming that continually threatened the Burmese capital itself, and ransacked Upper Burma districts. On 4 June 1661, Pye Min overthrew his ineffectual brother, and took over the command. He finally drove out the Ming by November 1661. The problems were not yet over for the Burmese. On 21 December 1661, a Qing army of 20,000 under Gen. Wu Sangui showed up at Ava, demanding the surrender of the Ming emperor. The emperor was handed over on 15 January 1662, and the Qing forces left a week later. 
Question: How many months after King Pindale sent the five regiments to the front were they sent back by the Ming? 
Answer type: Number 
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
2.