import java.util.*

val sc = Scanner(System.`in`)
val A = sc.nextInt()
val B = sc.nextInt()
val S:String = sc.next()

fun main(args: Array<String>) {
    var flg = false

    for (i in 0 until S.length) {
        if (i == A) {
            if (S[i] != '-') {
                flg = true
            }
        } else {
            if (S[i] == '-') {
                flg = true
            }
        }
    }
    println(arrayOf("Yes","No")[if (flg) 1 else 0])
}
