Detailed Instructions: You are given a paragraph, with numbered sentences, and a question. Write the numbers of the sentences needed to answer the given question. Separate multiple sentence numbers with a comma (", "). E.g. "1, 2" would be the correct response if Sent 1 and Sent 2 are needed to answer the given question (do not include sentences that contain no information that is necessary to answer the question). Sort the sentence numbers in an increasing order (i.e., '1, 2', instead of '2, 1'). Your answer should not contain anything than the sentence numbers separated by a comma (e.g. '1, 2, 3, 4'). The given question requires more than one sentence to answer. So, your answer must contain at least one comma (", ").
Q: Paragraph- Sent 1: Tocqueville's opposition to the invasion of Kabylie In opposition to Olivier Le Cour Grandmaison, Jean-Louis Benoit claimed that given the extent of racial prejudices during the colonization of Algeria, Tocqueville was one of its "most moderate supporters".
Sent 2: Benoit claimed that it was wrong to assume Tocqueville was a supporter of Bugeaud, despite his 1841 apologetic discourse.
Sent 3: It seems that Tocqueville modified his views after his second visit to Algeria in 1846; he criticized Bugeaud's desire to invade Kabylie in an 1847 speech to the Assembly.
Sent 4: Although Tocqueville had favoured retention of distinct traditional law, administrators, schools, etc., for Arabs who had come under French control, he judged the Berber tribes of Kabylie (in his second of Two Letters on Algeria, 1837) as "savages" not suited for this arrangement; they would best be managed, he argued, not by force of arms, but by the pacifying influences of commerce and cultural interaction.
Sent 5: Tocqueville's views on the matter were complex.
Sent 6: Even though in his 1841 report on Algeria he applauded Bugeaud for making war in a way that defeated Abd-el-Kader's resistance, he had advocated in the Two Letters that the French military advance leave Kabylie undisturbed, and in subsequent speeches and writings he continued to oppose intrusion into Kabylie.
Sent 7: In the debate about the 1846 extraordinary funds, Tocqueville denounced Bugeaud's conduct of military operations, and succeeded in convincing the Assembly not to vote funds in support of Bugeaud's military columns.
Sent 8: Tocqueville considered Bugeaud's plan to invade Kabylie, despite the opposition of the Assembly, as a seditious act in the face of which the government was opting for cowardice. 
Question: How many years passed from Tocqueville's initial Two Letters report to his second visit to Algiers which apparently led him to modify his views?.
A:
3, 4.