Teacher: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.
Teacher: Now, understand the problem? Solve this instance: Passage: On 28 April 1724, the city of Emden called on its possession Oldersum to prepare for war and arm themselves. On 2 February 1726, troops from Emden fought a battle in Leer against the princely troops. The latter were victorious. Soon afterwards, the renitent faction was condemned in an imperial decree. The conflict, however, continued and on 7 April 1726, another battle was fought in the streets of Leer, killing and wounding many soldiers. In April 1727, the Prince called in reinforcements from Denmark. A group of 60 men from Oldersum united with troops from Emden and other localities in the Emden area and marched to Norden, where they lost another battle against the Prince's army. Another imperial decree again condemned the renitent faction and ordern them to pay reparations. The Prince took over the administration of Oldersum from the city of Emden, and imperial troops occupied the castle at Oldersum. When the conflict ended, the Prince emerged victoriously and the recalcitrant city of Emden had to submit to him. However, the Prince had won a Pyrrhic victory. 
Question: How many years after Oldersum was advised to prepare for war was the first battle in Leer? 
Answer type: Number 
Student:
2.