import java.util.stream.Collectors

fun main(args: Array<String>) {
    val (a, b) = readLine()!!.split(" ").stream().map { it.toInt() }.collect(Collectors.toList())
    val s = readLine()!!

//    println(a)
//    println(b)
//    println(s)

    if (s[a] != '-') {
        println("No")
        return;
    }

    var flag = true

    for (i in 0..a-1) {
//        println(s[i])
//        println(flag)
        try {
            if (!s[i].isDigit()) {
                flag = false
            }
        } catch (e: Exception) {
            flag = false
        }
    }

    for (i in a+1..a+b) {
//        println(s[i])
//        println(flag)
        try {
            if (!s[i].isDigit()) {
                flag = false
            }
        } catch (e: Exception) {
            flag = false
        }
    }

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