context: As the longest-serving state governor, Cutler occasionally acted as Administrator of the Commonwealth of Australia in the absence of the Governor-General of Australia. He acted as Administrator during John Kerr (governor-general)s term from 20 February – 13 March 1975, 12–24 May 1975, 16–17 September 1975, 23 December 1975 – 3 February 1976, 26 April – 14 June 1977 and finally 23–28 August 1977.  Cutler was also scheduled to act during November 1975, when Kerr had planned an overseas holiday.  However, in view of the developing situation in Canberra, Kerr cancelled his travel bookings. In 1975, Cutlers advice to Kerr that he should warn Prime Minister Gough Whitlam of his 1975 Australian constitutional crisis, was ignored. Cutler later said that, had he been Administrator at the time, he would certainly have accepted his prime ministers advice and he would have allowed the parliament to resolve the issue without recourse to any such drastic action as dismissal.
question: How many months passed between the first and last times that Cutler served as Administrator?
answer: 30