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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"fmt"
	"unicode"
)

var A, B int
var S string

func main() {
	fmt.Scanf("%d %d", &A, &B)
	fmt.Scanf("%s", &S)

	ok := true
	if len(S) != A+B+1 {
		ok = false
	} else {
		for i := 0; i < len(S); i++ {
			if i == A {
				if S[i] != '-' {
					ok = false
				}
			} else if !unicode.IsDigit([]rune(S)[i]) {
				ok = false
			}
		}
	}

	if ok {
		fmt.Println("Yes")
	} else {
		fmt.Println("No")
	}
}