'X' was an Indian politician, lawyer, and journalist who was the first president of the Republic of India from 1950 to 1962. He also was a comrade of Mahatma Gandhi early in the noncooperation movement for independence and was the president of the Indian National Congress. In 1946, 'X's' autobiography- 'Atmakatha' was published and in 1962, he was honoured with the Bharat Ratna, India's highest civilian award. Identify 'X'.