let N = stdin.ReadLine() |> int
if N = 0 then 0
else
    stdin.ReadLine().Split(' ')
    |> Seq.map int
    |> Set.ofSeq
    |> Seq.pairwise
    |> Seq.map (fun (a,b) -> abs(a-b))
    |> Seq.min
|> printfn "%d"