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: Runtime Error)

package main 
import (
        "fmt"
)

func main () {
        var a, b, an int
        var s string
        fmt.Scan(&a,&b,&s)
        for i := 0 ; i < a ; i++{
                ii := i + 1
                if s[i:ii] == "-"{
                        an +=1
                }
        }
        if s[a:b] != "-" {
                an +=1
        }
        for i := b ; i < a + b + 1 ; i++ {
                ii := i + 1
                if s[i:ii] == "-" {
                        an +=1
                }
        } 
        if an == 0 {
        fmt.Println("Yes")
        }  else if an != 0{
        fmt.Println("No")
        }
}