f :: (Int, Int) -> Char -> (Int, Int)
f (v,a) 'D' = (if a == 0 then v + 1 else v, a - 1)
f (v,a) 'U' = (v, a + 1)
f x _ = x

main :: IO ()
main = do
  count <- getLine
  steps <- getLine
  print $ fst $ foldl f (0,0) steps