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)

object Main extends App {
	val ab = scala.io.StdIn.readLine.split(" ").map(_.toInt)
	val s = scala.io.StdIn.readLine.toList

	var flag = true
	var temp1 = ab(0)
	var temp2 = ab(1)

	for(i<-s){
		if(i != '-' && flag) temp1 = temp1 - 1
		else if(i != '-' && ! flag) temp2 = temp2 - 1
		else flag = false
	}

	if(temp1 == 0 && temp2 == 0)  println("Yes")
	else println("No")

}