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 Perl (v5.18.2) (judge verdict: Accepted)

#!/usr/bin/perl

my $l1 = <STDIN>;

$l1 =~ /^(\d+)\s+(\d+)/o;

my $a = $1;
my $b = $2;

my $l2 = <STDIN>;
$l2 =~ s/[\x00-\x20]+$//o;

if( $l2 =~ /^(\d*)-(\d*)$/o ){
  my $al = $1;
  my $bl = $2;
  if( length($al) == ($a - 0) and length($bl)== ($b - 0) ){
    print "Yes\n";
  } else {
    print "No\n";
  }
} else {
   print "No\n";
}