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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Linq;
using System.Collections.Generic;
using static System.Console;

class Program {
    internal static void Main(string[] args) {
        var inp = ReadLine().Split(' ').Select(s => int.Parse(s)).ToList();
        var S = ReadLine();
        var c = S.ToCharArray();
        var ans = "No";

        for (int i = 0; i < inp[0] + inp[1];i++) {
            if (i < inp[0]) {
                if (c[i] < '0' || c[i] > '9') {
                    ans = "No";
                    break;
                }
            } else if (i == inp[0]) {
                if (!(c[i] == '-')) {
                    ans = "No";
                    break;
                }
            } else {
                if (c[i] < '0' || c[i] > '9') {
                    ans = "No";
                    break;
                }
            }
            ans = "Yes";
        }

        WriteLine(ans);
    }
}