import java.io.{BufferedOutputStream, BufferedReader, InputStreamReader, PrintWriter}

object Main {
  def main(args: Array[String]): Unit = {
    val in = new BufferedReader(new InputStreamReader(System.in))
    val out = new PrintWriter(new BufferedOutputStream(System.out))
    val s = in.readLine()

    out.println(
      if (s == "AAA" || s == "BBB") {
        "No"
      } else {
        "Yes"
      }
    )
    out.flush()
  }
}
