import java.util.Scanner

object Main {
  def main(args: Array[String]): Unit = println(solve(new Scanner(System.in)))

  def solve(in: String): String = solve(new Scanner(in))

  def solve(sc: Scanner): String = {
    val N = sc.nextInt
    val X = sc.nextInt
    val x = (Array.fill(N)(sc.nextInt) :+ X).sorted

    val result = (for (i <- 1 to N) yield x(i) - x(i - 1)).min

    result.toString
  }
}
