object Main {
  def main(args: Array[String]): Unit = {
    val n = readLine.toInt
    val input = (1 to n map { _ => readLine.toInt }).toList
    // println(input)

    def calMaxProf(input: List[Int], maxProf: Int = Int.MinValue): Int = input match {
      case head :: Nil =>
        maxProf
      case head :: tail =>
        val prof = tail.map(_ - head).max
        if (prof > maxProf) {
          calMaxProf(tail, prof)
        } else {
          calMaxProf(tail, maxProf)
        }
      case Nil =>
        maxProf
    }

    println(calMaxProf(input))
  }
}

