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 (2.7.6) (judge verdict: Accepted)

# coding:utf-8                                                                                     

A, B = map(int, raw_input().split())
S = raw_input()

flag = False
if S[A] == '-':
    Ss = S.split('-')
    if len(Ss) == 2:
        if len(Ss[0]) == A and len(Ss[1]) == B:
            if Ss[0].isdigit() and Ss[1].isdigit():
                flag = True

if flag:
    print 'Yes'
else:
    print 'No'