module Main where

import Data.List

main :: IO ()
main = do
  { [l] <- getInts
  ; [n] <- getInts
  ; ws  <- getInts
  ; print $ length $ unfoldr phi (l,sort ws)
  }
  
phi :: (Int,[Int]) -> Maybe ((),(Int,[Int]))
phi (_,[]) = Nothing
phi (0,_)  = Nothing
phi (x,y:ys)
  | x < y     = Nothing
  | otherwise = Just ((),(x-y,ys))

getInts :: IO [Int]
getInts = map read . words <$> getLine