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 C++14 (Clang 3.8.0) (judge verdict: Accepted)

#include <iostream>

int main(void)
{
    int a, b;
    std::string s;
    std::cin >> a >> b >> s;
    bool flag = true;
    for (int i = 0; i < int(s.size()); ++i)
    {
        if (i == a)
        {
            flag &= (s[i] == '-');
        }
        else
        {
            flag &= ('0' <= s[i]) && (s[i] <= '9');
        }
    }
    std::cout << (flag ? "Yes" : "No") << std::endl;
}