import Data.List

dif f (x:y:[]) = [f x y]
dif f (x:y:xs) = (f x y) : (dif f (y:xs))

main = do
	n <- getLine
	p <- getLine >>= return . nub . sort . map (read::String->Int) . words
	print $ if length p == 0
		then 0
		else minimum $ dif (\x y -> abs (x-y)) p