Problem:
Score : 200 points

Problem Statement

Takahashi's house has only one socket.

Takahashi wants to extend it with some number of power strips, each with A sockets, into B or more empty sockets.

One power strip with A sockets can extend one empty socket into A empty sockets.

Find the minimum number of power strips required.

Constraints

All values in input are integers.

2 \leq A \leq 20

1 \leq B \leq 20

Input

Input is given from Standard Input in the following format:

A B

Output

Print the minimum number of power strips required.

Sample Input 1

4 10

Sample Output 1

3

3 power strips, each with 4 sockets, extend the socket into 10 empty sockets.

Sample Input 2

8 9

Sample Output 2

2

2 power strips, each with 8 sockets, extend the socket into 15 empty sockets.

Sample Input 3

8 8

Sample Output 3

1

Solution in Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"strconv"
)

func run() {
	a := nextInt()
	b := nextInt()
	ans := 0
	cur := 1
	for cur < b {
		cur = cur + a - 1
		ans++
	}
	Println(ans)
}

// --- template ---
// Thanks https://gist.github.com/halllllll/853ab587fd82ee3ffe6f7fb7fb499695

var sc = bufio.NewScanner(os.Stdin)
var out = bufio.NewWriter(os.Stdout)

// Caution: You will get unexpected result if a single token is larger than this size.
const BufferSize = 64 * 1024 * 1024

func Print(a ...interface{}) (n int, err error) {
	return fmt.Fprint(out, a...)
}

func Printf(format string, a ...interface{}) (n int, err error) {
	return fmt.Fprintf(out, format, a...)
}

func Println(a ...interface{}) (n int, err error) {
	return fmt.Fprintln(out, a...)
}

func next() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	a, err := strconv.Atoi(next())
	if err != nil {
		log.Fatal(err)
	}
	return a
}

func nextFloat() float64 {
	a, err := strconv.ParseFloat(next(), 64)
	if err != nil {
		log.Fatal(err)
	}
	return a
}

func main() {
	sc.Buffer(make([]byte, 0, BufferSize), BufferSize)
	sc.Split(bufio.ScanWords)
	run()
	out.Flush()
}