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.
Q: Passage: In 1509, Diogo Lopes de Sequeira was sent to Malacca by the king of Portugal with four ships in order to establish contact with the Sultanate of Malacca. Initially, Sequeira was well received by the Sultan Mahmud Syah . Soon however, the Muslim community convinced Mahmud Syah that the Portuguese should be eliminated. Several men were captured and killed, but the ships escaped. Albuquerque first departed from India for Malacca in April 1511, with 1,200 men and 17 to 18 ships. Albuquerque's objective was to sever Islamic trade and Venetian trade on the same occasion.A first attack by the Portuguese failed on 25 July 1511. Albuquerque's captains spoke against another attempt, but he struck again, succeeding in capturing Malacca in August, despite strong resistance and the presence of artillery on the Malaccan side. In celebration, Tristao da Cunha was sent to Pope Leo X in Rome with rich presents including the elephant that the pope named Hanno.
Question: How many ships were able to escape?
Answer type: Number
A:
4.