{"pre_text": ["as of december 31 , 2017 , the aggregate future minimum payments under non-cancelable operating leases consist of the following ( in thousands ) : years ending december 31 ."], "post_text": ["rent expense for all operating leases amounted to $ 9.4 million , $ 8.1 million and $ 5.4 million for the years ended december 31 , 2017 , 2016 and 2015 , respectively .", "financing obligation 2014build-to-suit lease in august 2012 , we executed a lease for a building then under construction in santa clara , california to serve as our headquarters .", "the lease term is 120 months and commenced in august 2013 .", "based on the terms of the lease agreement and due to our involvement in certain aspects of the construction , we were deemed the owner of the building ( for accounting purposes only ) during the construction period .", "upon completion of construction in 2013 , we concluded that we had forms of continued economic involvement in the facility , and therefore did not meet with the provisions for sale-leaseback accounting .", "we continue to maintain involvement in the property post construction and lack transferability of the risks and rewards of ownership , due to our required maintenance of a $ 4.0 million letter of credit , in addition to our ability and option to sublease our portion of the leased building for fees substantially higher than our base rate .", "therefore , the lease is accounted for as a financing obligation and lease payments will be attributed to ( 1 ) a reduction of the principal financing obligation ; ( 2 ) imputed interest expense ; and ( 3 ) land lease expense , representing an imputed cost to lease the underlying land of the building .", "at the conclusion of the initial lease term , we will de-recognize both the net book values of the asset and the remaining financing obligation .", "as of december 31 , 2017 and 2016 , we have recorded assets of $ 53.4 million , representing the total costs of the building and improvements incurred , including the costs paid by the lessor ( the legal owner of the building ) and additional improvement costs paid by us , and a corresponding financing obligation of $ 39.6 million and $ 41.2 million , respectively .", "as of december 31 , 2017 , $ 1.9 million and $ 37.7 million were recorded as short-term and long-term financing obligations , respectively .", "land lease expense under our lease financing obligation amounted to $ 1.3 million for each of the years ended december 31 , 2017 , 2016 and 2015 respectively. ."], "table": [["2018", "$ 9127"], ["2019", "8336"], ["2020", "8350"], ["2021", "7741"], ["2022", "7577"], ["thereafter", "9873"], ["total minimum future lease payments", "$ 51004"]], "table_ori": [["2018", "$9,127"], ["2019", "8,336"], ["2020", "8,350"], ["2021", "7,741"], ["2022", "7,577"], ["Thereafter", "9,873"], ["Total minimum future lease payments", "$51,004"]]}

Question: what is the total rent expense for the period from december 31 , 2017 , 2016 and 2015 in millions
Evidence:
text_1: rent expense for all operating leases amounted to $ 9.4 million , $ 8.1 million and $ 5.4 million for the years ended december 31 , 2017 , 2016 and 2015 , respectively .
Program: add(9.4, 8.1), add(#0, 5.4)
Answer:
str_answer: 22.9
exe_answer: 22.9