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))
       (as (subseq s 0 a))
       (cs (subseq s a (1+ a)))
       (bs (subseq s (1+ a))))
      (if (and (every #'digit-char-p as)
               (equal cs "-")
               (every #'digit-char-p bs))
          (princ "Yes")
          (princ "No")))