object Main {
  def main(args: Array[String]): Unit = {
    val sc = new java.util.Scanner(System.in)
    val n = sc.next()

    val result = (n.charAt(0) == n.charAt(1) && n.charAt(1) == n.charAt(2))

    val ans = if (result) "No" else "Yes"
    println(ans)
  }
}
