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 Common Lisp (SBCL 1.1.14) (judge verdict: Accepted)

(let ((a (read))
      (b (read))
      (s (read-line)))
  (princ
   (if (and (= (length s) (+ a b 1))
            (char= (aref s a) #\-)
            (not (member #\- (concatenate 'list
                                          (subseq s 0 a)
                                          (subseq s (1+ a) (+ a b 1))))))
       "Yes"
       "No"))
  (terpri))