Given the task definition and input, reply with output. 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.

Passage: The Relief of Genoa took place between 28 March 1625 and 24 April 1625, during the Thirty Years' War. It was a major naval expedition launched by Spain against the French-occupied Republic of Genoa, of which the capital Genoa was being besieged by a joint Franco-Savoyard army composed of 30,000 men and 3,000 cavalry. In 1625, when the Republic of Genoa, traditionally an ally of Spain, was occupied by French troops of the Duke of Savoy, the city underwent a hard siege. It was known in Genoese governmental circles that one of the reasons why the Dutch government had offered their help to the Franco-Savoyan army was so that they could "hit the bank of the King of Spain". However, the Spanish fleet commanded by General Alvaro de Bazan, Marquis of Santa Cruz, came to the aid of Genoa and relieved the city. Returning its sovereignty to the Republic of Genoa and forcing the French to raise the siege, they consequently began a combined campaign against the Franco-Savoyan forces that had overrun the Genoese Republic one year before. The joint Franco-Piedmontese army was forced to leave Liguria and Spanish troops invaded Piedmont, thereby securing the Spanish Road. Richelieu's Invasion of Genoa and the Valtelline had resulted in his humiliation by the Spaniards.
Question: How many days did the Relief of Genoa take place?
Answer type: Number
28.