Helen cuts her lawn starting in March and finishes in October.  Her lawn mower uses 2 gallons of gas every 4th time she cuts her lawn.  For March, April, September and October, she only cuts her law 2 times per month.  In May, June, July and August, she has to cut her lawn 4 times per month.  How many gallons of gas will she need to cut her lawn from March through October?
Please reason step by step, and put your final answer within \boxed{}.
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