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 Lua (5.3.2) (judge verdict: Accepted)

local a, b = io.read("*n", "*n", "*l")
local s = io.read()
local f = true
for i = 1, #s do
  if i == a + 1 then
    if s:sub(i, i) ~= "-" then f = false break end
  else
    local c = s:sub(i, i):byte()
    if c < 48 or 57 < c then
      f = false
      break
    end
  end
end
print(f and "Yes" or "No")