-- Find the thirteen adjacent digits in the 1000-digit number that
-- have the greatest product. What is the value of this product?
import Data.List

number = "73167176531330624919225119674426574742355349194934" ++
         "96983520312774506326239578318016984801869478851843" ++
         "85861560789112949495459501737958331952853208805511" ++
         "12540698747158523863050715693290963295227443043557" ++
         "66896648950445244523161731856403098711121722383113" ++
         "62229893423380308135336276614282806444486645238749" ++
         "30358907296290491560440772390713810515859307960866" ++
         "70172427121883998797908792274921901699720888093776" ++
         "65727333001053367881220235421809751254540594752243" ++
         "52584907711670556013604839586446706324415722155397" ++
         "53697817977846174064955149290862569321978468622482" ++
         "83972241375657056057490261407972968652414535100474" ++
         "82166370484403199890008895243450658541227588666881" ++
         "16427171479924442928230863465674813919123162824586" ++
         "17866458359124566529476545682848912883142607690042" ++
         "24219022671055626321111109370544217506941658960408" ++
         "07198403850962455444362981230987879927244284909188" ++
         "84580156166097919133875499200524063689912560717606" ++
         "05886116467109405077541002256983155200055935729725" ++
         "71636269561882670428252483600823257530420752963450"

main = print $ maximum $ map (product . take 13) $ take 988 $
       tails $ map (read . (:[])) number