Problem:
Score : 200 points

Problem Statement

The postal code in Atcoder Kingdom is A+B+1 characters long, its (A+1)-th character is a hyphen -, and the other characters are digits from 0 through 9.

You are given a string S. Determine whether it follows the postal code format in Atcoder Kingdom.

Constraints

1≤A,B≤5

|S|=A+B+1

S consists of - and digits from 0 through 9.

Input

Input is given from Standard Input in the following format:

A B
S

Output

Print Yes if S follows the postal code format in AtCoder Kingdom; print No otherwise.

Sample Input 1

3 4
269-6650

Sample Output 1

Yes

The (A+1)-th character of S is -, and the other characters are digits from 0 through 9, so it follows the format.

Sample Input 2

1 1
---

Sample Output 2

No

S contains unnecessary -s other than the (A+1)-th character, so it does not follow the format.

Sample Input 3

1 2
7444

Sample Output 3

No

Solution in Scala (2.11.7) (judge verdict: Accepted)

import java.util.Scanner

object Main extends App {
  val sc = new Scanner(System.in)
  val a, b = sc.nextInt()
  val s = sc.next()

  val split = s.split("-")

  def isNums(str: String) = str.toList.forall(c => c.isDigit)

  def isOK(): Boolean = {
    if (split.length == 2) {
      val p1 = split(0)
      val p2 = split(1)
      if (p1.length == a && p2.length == b) {
        if (isNums(p1) && isNums(p2)) {
          return true
        }
      }
    }
    return false
  }

  val result = if (isOK()) "Yes" else "No"
  println(result)
}