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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

    <?php
    fscanf(STDIN, "%d %d", $a, $b);
    fscanf(STDIN, "%s", $s);
    $pos = strpos($s, '-');
    //var_dump($pos);
    if($pos === $a) {
        if(is_numeric($a) && is_numeric($b) &&
            strlen($s) === $a + $b + 1) {
            echo 'Yes'. "\n";
        } else {
            echo 'No'. "\n";
        }
    } else {
        echo 'No'. "\n";
    }