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: Runtime Error)

import sys

# 関数 solve は，もちろん，問題に応じて書き換える
def solve( lst_a, lst_b,n):
    if n.count("-")==1:
        answer= "No"
    else:
        N,NN=n.split("-")
        if lst_a == len(N) and lst_b == len(NN):
            answer = "Yes"
        else:
            answer = "No"
    return answer

# ここから下は，入力・出力形式が同じであれば，変えなくて良い．
def readQuestion():
    line1 = sys.stdin.readline().rstrip()
    [str_n, str_i] = line1.split(' ')
    line2 = sys.stdin.readline().rstrip()
    return (int(str_n), int(str_i), line2)

def main():
    n, i, s = readQuestion()
    answer = solve(n, i, s)
    print(answer)
    
if __name__ == '__main__':
    main()