import java.util.Scanner

object Main {
  def main(args: Array[String]): Unit = {
    //nextLineとnextを同時に使ったら死ぬ
    val sc = new Scanner(System.in)
    val a, b = sc.nextInt()
    val s = sc.next()

    var flag = true

    for (i <- s.indices) {
      if (i == a) {
        flag = flag && s(i) == '-'
      } else {
        flag = flag && "0123456789".contains(s(i))
      }
    }

    println(if (flag) {
      "Yes"
    } else {
      "No"
    })
  }
}
