import Control.Applicative ((<$>))
import Control.Monad
import Data.List

import Data.Char (isSpace)
import qualified Data.ByteString.Char8 as B8

import Data.Set (Set)
import qualified Data.Set as S

main :: IO ()
main = do
  B8.getLine
  solve <$> readIntList >>= print

solve :: [Int] -> Int
solve xs = let s = foldl' f S.empty xs
           in if S.size s == 1 then 0 else fst . S.foldl' g (10000000, -10000000) $ s
  where
    f s x = S.insert x s
    g (d, x) y = (min d (y - x), y)

readIntList :: IO [Int]
readIntList = unfoldr f <$> B8.getLine
  where
    f s = do
      (n, s') <- B8.readInt s
      return (n, B8.dropWhile isSpace s')