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.
One example: Passage: The outbreak of the Seven Years' War in Europe in 1756 resulted in renewed conflict between French and British forces in India. The Third Carnatic War spread beyond southern India and into Bengal where British forces captured the French settlement of Chandernagore in 1757. However, the war was decided in the south, where the British successfully defended Madras, and Sir Eyre Coote decisively defeated the French, commanded by Comte de Lally at the Battle of Wandiwash in 1760. After Wandiwash, the French capital of Pondicherry fell to the British in 1761. The war concluded with the signing of the Treaty of Paris in 1763, which returned Chandernagore and Pondichery to France, and allowed the French to have "factories" in India but forbade French traders from administering them. The French agreed to support British client governments, thus ending French ambitions of an Indian empire and making the British the dominant foreign power in India.
Question: Which french settlement did the British capture first, Chandernagore or Pondicherry
Answer type: Span
Solution is here: Chandernagore
Explanation: British captured Chandernagore in 1757 ("The Third Carnatic War spread beyond southern India and into Bengal where British forces captured the French settlement of Chandernagore in 1757") and Pondicherry in 1761 ("After Wandiwash, the French capital of Pondicherry fell to the British in 1761."). Since 1757<1761, the answer is "Chandernagore".

Now, solve this: Passage: The size of the indemnity had been the hardest factor to accept for the Tibetan negotiators. The Secretary of State for India, St John Brodrick, had in fact expressed the need for it to be "within the power of the Tibetans to pay" and given Younghusband a free hand to be "guided by circumstances in this matter". Younghusband raised the indemnity demanded from 5,900,000 to 7,500,000 rupees, and further demanded the right for a British trade agent, based at Gyantse, to visit Lhasa "for consultations". It seems that he was still following Lord Curzon's geo-political agenda to extend British influence in Tibet by securing the Chumbi Valley for Britain. Younghusband wanted the payment to be met by yearly instalments; it would have taken about 75 years for the Tibetans to clear their debt, and since British occupation of the Chumbi valley was surety until payment was completed, the valley would remain in British hands. Younghusband wrote to his wife immediately after the signing; "I have got Chumbi for 75 years. I have got Russia out for ever". The regent commented that "When one has known the scorpion the frog is divine". The Amban later publicly repudiated the treaty, while Britain announced that it still accepted Chinese claims of authority over Tibet. Acting Viceroy Lord Ampthill reduced the indemnity by two-thirds and considerably eased the terms in other ways. The provisions of this 1904 treaty were revised in the Anglo-Chinese Convention of 1906. The British, for a fee from the Qing court, also agreed "not to annex Tibetan territory or to interfere in the administration of Tibet", while China engaged "not to permit any other foreign state to interfere with the territory or internal administration of Tibet".
Question: How many years were between the 1904 treaty and its revision?
Answer type: Number
Solution:
2.