Given the task definition and input, reply with output. In this task, you're given a question, along with three passages, 1, 2, and 3. Your job is to determine which passage can be used to answer the question by searching for further information using terms from the passage. Indicate your choice as 1, 2, or 3.

Question: How many years was the royal house named the House of Saxe-Coburg and Gotha before it was changed? Passage 1:He attended the Colegio San Luis Gonzaga and afterwards the Colegio Civil of Querétaro from 1883 to 1887. In 1892 he began his studies at the Escuela Nacional de Medicina (currently Faculty of Medicine of the UNAM) in Mexico City and graduated in 1893. As an officer candidate he completed the Escuela Práctica Médico-Militar (predecessor of the Escuela Médico Militar) at the military teaching hospital and made his specialty training in ophthalmology in the United States and in Canada from 1893 to 1895. In 1896 he married María Elvira Camarena Aldana and worked in Aguascalientes. He also was a liberal thinking politician, active in the city of Aguascalientes from 1903 to 1911 and as Deputy Governor of Aguascalientes from 1910 to 1911. From 1914 he served as a military surgeon on the side of revolutionary forces during the revolution, was promoted to the rank of Brigadier General (MC) in 1916. From June 1, 1916 to December 11, 1917 as well as from December 4, 1920 to December 16, 1934 he served as head of the medical branch in the Secretaría de Guerra y Marina. He was one of the founders of the Escuela Constitucionalista Médico Militar where he was director and taught as Professor of pathology, medical therapy and ophthalmology. From 1933 to 1934 he was director of the journal "Gaceta Médico Militar", the organ of the Mexican military branch. He died in Mexico City.
 Passage 2:Prior to taking up speedway, Charles worked as a baker and grocer, and performed in music halls with a piano accordion. In 1929 Charles rode for Burnley, in 1930 for Manchester White City and then for Leeds Lions and Belle Vue in 1931 but was badly injured and lost his form, and so retired from the sport. In 1933, the Belle Vue Aces tempted him out of retirement, and looked to have regained his former form when he won the Wembley championship that year, also breaking the track record. In 1934 Charles' father died, so he returned to the family business. In 1935 Wembley Lions paid £1,000 to sign Charles, where he became the club's top scorer and was selected to ride for England against Australia. He went on to win the Star Riders' Championship despite only initially taking part in the competition as a replacement for Ginger Lees. In 1936 he topped the club's scoring again, was top scorer for the England Test team, and qualified for World Championship final, tying for fourth place with Cordy Milne, and broke the track record during the meeting. He qualified again for the 1937 final. At the end of the 1938 season he decided to retire to concentrate on his long-term hobby of gliding.
 Passage 3:The programme explores the lives of King George V and Queen Mary, and their attempts at modernising the British Monarchy in response to the massive social changes during and following World War I. The first episode recalls how, fearing anti-German sentiment, the royal house name was changed by King George from the House of Saxe-Coburg and Gotha to the House of Windsor. The series also examines the personal lives of the couple, delving into their relationships with their children, and with each other. The marriage between George and Mary was an arranged marriage, occurring only because Prince Albert Victor, George's brother and Mary's original fiancé, died from influenza. George V is presented in the series as a disciplinarian, who strictly punished his children, but was known to be much more loving to his granddaughter, Queen Elizabeth II.
3