fun main(args: Array<String>) {
    val sc = java.util.Scanner(System.`in`)
    val A = sc.next().toInt()
    val B = sc.next().toInt()
    val S = sc.next()

    if (S.filter({c -> c == '-' }).length == 1) {
        if (S[A] == '-'){
            println("Yes")
            return
        }
    }
    println("No")
}