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 Pascal (FPC 2.6.2) (judge verdict: Accepted)

program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils;
var
  a,b,i:integer;
  s,ans:string;
begin
  try
    { TODO -oUser -cConsole Main : abc84a}
    read(a);
    readln(b);
    readln(s);

    ans:='Yes';
    if not(s[a+1]='-') then
      ans:='No'
    else begin
      for i := 1 to a do
        if s[i]='-' then begin
          ans:='No';
          break;
        end;
      for i := a+2 to Length(s) do
        if s[i]='-' then begin
          ans:='No';
          break;
        end;
    end;

    Writeln(ans);
    readln;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.