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()
accept = None

for i, c in enumerate(S):
    if i == A:
        if c != "-":
            accept = False
            break
    else:
        if c not in ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]:
            break
        elif i == A+B+1-1:
            accept = True
        else:
            accept = False

if accept:
    print("Yes")
else:
    print("No")