import Text.Parsec.String (Parser)
import Text.Parsec
import System.Environment
import Control.Monad
import Debug.Trace
import qualified Data.Map as M

num :: Parser Int
num = read <$> many1 digit

seeds :: Parser [Int]
seeds = string "seeds: " *> many1 (read <$> many1 digit <* space) <* newline

almanacTitle = (,) <$> many1 (noneOf "-") <* string "-to-" <*> many1 (noneOf " ") <* string " map:" 

mapLine = (,,) <$> num <* space <*> num <* space <*> num

almanacMap :: Parser ([(Int,Int,Int)])
almanacMap = almanacTitle *> newline *> sepEndBy mapLine newline

almanac = (,) <$> seeds <*> sepEndBy1 almanacMap newline

buildRange :: (Int,Int,Int) -> M.Map Int Int
buildRange (dst,src,len) = M.fromList $ zip [src..src+len-1] [dst..dst+len-1] 

sectionMap :: [(Int,Int,Int)] -> M.Map Int Int
sectionMap xs = M.unionsWith (const id) $ (M.fromList $ zip [0..99] [0..99]):map buildRange xs

locations :: ([Int], [[(Int,Int,Int)]]) -> [Int]
locations (seeds,sections) = do
    let maps = map sectionMap sections 
    seed <- seeds
    let location = foldr (M.!) seed (reverse maps)
    return location

solution = minimum . locations

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