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: Accepted)

<?php
fscanf(STDIN, "%d %d", $a, $b);
fscanf(STDIN, "%s", $s);
for($i = 0; $i < $a; $i++) {
    if(!is_numeric($s[$i]) || $s[$i] < 0 && $s[$i] > 9) {
        echo 'No'. "\n";
        exit;
    }
}
if($s[$a] != '-') {
    echo 'No'. "\n";
    exit;
}
for($i = $a + 1; $i < $a + $b + 1; $i++) {
    if(!is_numeric($s[$i]) || $s[$i] < 0 && $s[$i] > 9) {
        echo 'No'. "\n";
        exit;
    }
}
echo 'Yes'. "\n";