Task: Question Answering
Input (English): Passage: On 31 December 1543, Henry and Charles had signed a treaty pledging to invade France in person by 20 June 1544; each was to provide an army of no less than 35,000 infantry and 7,000 cavalry for the venture. Against this Francis could muster about 70,000 men in his various armies. The campaign could not begin, however, until Henry and Charles had resolved their personal conflicts with Scotland and the German princes, respectively. On 15 May, Henry was informed by Edward Seymour, Earl of Hertford, that, after his raids, Scotland was no longer in a position to threaten him; he then began to make preparations for a personal campaign in France—against the advice of his council and the Emperor, who believed that his presence would be a hindrance. Charles had meanwhile reached an understanding with the princes at the Diet of Speyer, and the Electors of Saxony and Brandenburg had agreed to join his invasion of France. By May 1544, two Imperial armies were poised to invade France: one, under Ferrante Gonzaga, Viceroy of Sicily, north of Luxemburg; the other, under Charles himself, in the Palatinate. Charles had gathered a combined force of more than 42,000 for the invasion, and had arranged for another 4,000 men to join the English army. On 25 May, Gonzaga captured Luxembourg and moved towards Commercy and Ligny, issuing a proclamation that the Emperor had come to overthrow "a tyrant allied to the Turks". On 8 July, Gonzaga besieged Saint-Dizier; Charles and the second Imperial army soon joined him. 
Question: How many days after Henry and Charles agreed to sign a treaty to invade France was the invasion of France to happen? 
Answer type: Number 
Output (English): 171.