
graph :: [[Integer]]
graph =
	[ [75]
	, [95,64]
	, [17,47,82]
	, [18,35,87,10]
	, [20,04,82,47,65]
	, [19,01,23,75,03,34]
	, [88,02,77,73,07,63,67]
	, [99,65,04,28,06,16,70,92]
	, [41,41,26,56,83,40,80,70,33]
	, [41,48,72,33,47,32,37,16,94,29]
	, [53,71,44,65,25,43,91,52,97,51,14]
	, [70,11,33,28,77,73,17,78,39,68,17,57]
	, [91,71,52,38,17,14,91,43,58,50,27,29,48]
	, [63,66,04,68,89,53,67,30,73,16,69,87,40,31]
	, [04,62,98,27,23,09,70,98,73,93,38,53,60,04,23] ]

calc_max_path_totals_for_row :: [Integer] -> [Integer] -> [Integer]
calc_max_path_totals_for_row row prev_row = zipWith max l_sums r_sums
	where
		l_sums :: [Integer]
		l_sums =		(zipWith (+) (init row) prev_row) ++ [0]
		
		r_sums :: [Integer]
		r_sums = [0] ++ (zipWith (+) (tail row) prev_row)

-- parallel to `graph`
max_path_totals :: [[Integer]]
max_path_totals = (:) (head graph) $
	zipWith
		calc_max_path_totals_for_row
		(tail graph)
		max_path_totals

main :: IO ()
main = do
	putStrLn . show $ maximum . last $ max_path_totals
