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)

var
n,m,i:longint;
s:string;
begin
readln(n,m);
read(s);
for i:=1 to n do
  if not(s[i] in['0'..'9']) then begin writeln('No');halt;end;
if s[n+1]<>'-' then begin writeln('No');halt;end;
for i:=n+2 to n+m+1 do
  if not(s[i] in['0'..'9']) then begin writeln('No');halt;end;
writeln('Yes');
end.