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 (1.14.1) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

func main() {
	sc = initScanner(os.Stdin)
	a, b := scanInt(sc), scanInt(sc)
	s := scanString(sc)

	fmt.Println(resolve(a, b, s))
}

func resolve(a int, b int, s string) string {
	ss := strings.Split(s, "")

	if ss[a] != "-" {
		return "No"
	}

	_, err := strconv.Atoi(strings.Join(ss[:a], ""))
	if err != nil {
		return "No"
	}

	_, err = strconv.Atoi(strings.Join(ss[a+1:], ""))
	if err != nil {
		return "No"
	}

	return "Yes"
}

// --------------- BASE DEFINITIONS ---------------

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords)
	return sc
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}

func scanIntSlice(sc *bufio.Scanner, n int) []int {
	is := make([]int, n)
	for i := 0; i < n; i++ {
		is[i] = scanInt(sc)
	}

	return is
}

func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}