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 Array(a, b) = in.readLine().split("\\s+").map(_.toInt)
    val s = in.readLine()

    out.println(
      if (s.length == a + b + 1 && s(a) == '-' && s.filter(c => c >= '0' && c <= '9').length == a + b) {
        "Yes"
      } else {
        "No"
      }
    )

    out.flush()
  }
}
