import qualified Data.ByteString.Char8 as C
import Data.Char
import Data.Array.IO

main :: IO ()
main = do
  s1 <- C.getLine
  let (n,r1) = nextInt s1
  s2 <- C.getLine
  let a = solve s2
  s3 <- C.getLine
  let (b,r2) = nextInt s3
  print $ a - b

solve :: C.ByteString -> Int
solve ss
  | C.null ss = 0
  | otherwise = x + solve rs
  where (x,rs) = nextInt ss
  
nextInt :: C.ByteString -> (Int, C.ByteString)
nextInt ss
  | isDigit x || x == '-' = nextInt2 0 ss
  | otherwise             = nextInt $ C.tail ss
  where x = C.head ss

nextInt2 :: Int -> C.ByteString -> (Int, C.ByteString)
nextInt2 n ss
  | C.null ss = (n, ss)
  | y == '-'  = (-z,zs)
  | isDigit y = nextInt2 (n * 10 + (digitToInt y)) ys
  | otherwise = (n, ys)
  where y  = C.head ss
        ys = C.tail ss
        (z,zs) = nextInt2 0 ys