import Data.Foldable
main::IO()
main = do
  w <-fmap read getLine
  d <-fmap read getLine
  let f1 (w,r) d = (w-amt,amt)
        where amt = truncate $ fromIntegral w / fromIntegral(d*d)
  
  print . snd . foldl' f1 (w,0) $[d,(d-1)..1]