import Text.Parsec.String (Parser)
import Text.Parsec
import System.Environment
import Control.Monad
import Debug.Trace

data Tile = EmptyT | Digit Int | Symbol deriving (Show,Eq)

tile :: Parser Tile
tile = char '.' *>  pure EmptyT <|> Digit <$> (read.pure <$> digit) <|> noneOf "\n" *> pure Symbol 

board = sepBy (many1 tile) newline

symbolPositions l = [(x,y) | (y,r) <- zip [0..] l, (x,Symbol) <- zip [0..] r]

digitPositions l = [(n,x,y) | (y,r) <- zip [0..] l, (x,Digit n) <- zip [0..] r]

groupBy :: (a -> a -> Bool) -> [a] -> [[a]]
groupBy p = map (uncurry (:)) . groupByNonEmpty p

groupByNonEmpty :: (a -> a -> Bool) -> [a] -> [(a,[a])]
groupByNonEmpty p =
   foldr
      (\x0 yt ->
         let (xr,yr) =
               case yt of
                  (x1,xs):ys ->
                     if p x0 x1
                       then (x1:xs,ys)
                       else ([],yt)
                  [] -> ([],yt)
         in  (x0,xr):yr)
      []

fromDigits :: [Int] -> Int
fromDigits = foldl ((+) . (10 *)) 0

neighbours = foldMap (\(x,y) -> map (\(dx,dy) -> (x+dx,y+dy)) neigh) where
    neigh = liftM2 (,) [1,0,-1] [1,0,-1]

solution :: [[Tile]] -> Int
solution board = sum $ map (fromDigits.map (\(n,_,_) -> n)) partNumbers where
    blacklisted = neighbours $ symbolPositions board 
    digs = groupBy (\(_,x1,_) (_,x2,_) -> x2 == succ x1) $ digitPositions board
    partNumbers = filter (\l -> any (\(_,x,y) -> (x,y) `elem` blacklisted) l) $ digs


main = liftM2 (>>=) readFile (((print . solution . either (error.show) id) .) . parse board) =<< head <$> getArgs