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 Ruby (2.7.1) (judge verdict: Wrong Answer)

A,B = gets.split(' ').map(&:to_i)
S = gets.to_s
flag = 0
numbers = 0..9

if S.size == (A + B + 1)
	if S[A] == '-'
		S.size.times do |i|
			if i != A
				flag = 0 unless numbers.include?(S[i])
			end
			if flag == 1
				puts 'No'
				exit
			end
		end
		puts 'Yes' if flag == 0
	else
		puts 'No'
		exit		
	end
else
	puts 'No'
	exit
end