object Solution {

  def main(args: Array[String]): Unit = {
    val sc = new java.util.Scanner(System.in)
    val n = sc.nextInt()
    val nums = new Array[Int](n)

    nums.indices.foreach(i => nums(i) = sc.nextInt())

    val sorted = nums.sorted
    val distinct = sorted.distinct

    def thisAsCenter(k: Int) = {
      val numEqual = sorted.count(_ == k)
      val oneLess = sorted.count(_ == k-1)
      val oneMore = sorted.count(_ == k+1)
      
      numEqual + Math.max(oneLess, oneMore)
    }

    val solution = distinct.map(thisAsCenter(_)).max

    println(solution)

  }
}