In October 1932, the Judicial Secretary, A.C.Davies, as directed by the Governor in Council asked the DIG  to suggest the names of the revolutionary convicts with a statement showing the offences for which they had been convicted, the sentence awarded and a brief note showing their connection with the revolutionary movement with a view to transferring them to the Andamans. The DIG  suggested the names of Yogendra Shukla, Basawon Singh , Shyamdeo Narayan alias Ram Singh, Ishwar Dayal Singh, Kedar Mani Shukla, Mohit Chandra Adhikari and Ram Pratap Singh. Yogendra Shukla, Kedar Mani Shukla and Shyamdeo Narayan were transferred to the Andamans in December, 1932. In 1937, Yogendra Shukla was transferred to Hazaribagh Central Jail as a result of his 46 days of hunger strike. When Sri Krishna Sinha formed the first Congress ministry in 1937, he took up the cause of political prisoners and his ministry resigned on the issue on 15 February 1938. As a result, the Viceroy conceded the demands and Yogendra Shukla along with other political prisoners was released in March, 1938.
Question: How many years did it take for Krishna Sinha's Congress ministry to resign?
Answer: 1