let read () = Scanf.scanf "%d " (fun i -> i)

let () =
  let n = read () in
  let a = Array.init n (fun _ -> read ()) in
  Array.fast_sort (-) a;
  let rec doit i m =
    if i = n then m
    else
      let x = a.(i) - a.(i-1) in
      doit (i + 1) (if x = 0 then m else min m x) in
  let m = doit 1 max_int in
  Printf.printf "%d\n" (if m = max_int then 0 else m)