import Data.List

rInt :: String -> Int
rInt = read

solve n xs
    | n == 1 || length xs == 1  = 0
    | otherwise                 = minimum $ zipWith (-) (tail xs) (init xs)

main = do
    n <- rInt <$> getLine
    xs <- map head . group . sort . map rInt . words <$> getLine
    print $ solve n xs