import Control.Monad
import Control.Applicative
import Data.List
import qualified Data.Map as Map
import Data.Array
import qualified Data.ByteString.Char8 as BC
import Data.Maybe
readInts = map (fst . fromJust . BC.readInt) . BC.words <$> BC.getLine
readInt :: BC.ByteString -> Int
readInt = fst . fromJust . BC.readInt
strToInt s = (read :: String -> Int) s
    
main = do
    n <- readLn
    xsn <- map readInt . BC.words <$> BC.getLine
    let xs = sort xsn
    if n==1 then print 0
            else print $ maximum [abs((xs!!i)-(xs!!(i+1))) | i <-[1..(n-2)]]