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 Python (3.4.3) (judge verdict: Accepted)

a,b=map(int,input().split())
s=input()
def dig(s):
    if "0"<=s<="9":
        return True
    else: return False

def dig2(s,a,b):
    for i in s[:a]:
        if not dig(i):
            return False
    if s[a]!='-':
        return False

    for i in s[a+1:]:
        if not dig(i):
            return False
    return True

print(["No","Yes"][dig2(s,a,b)])