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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

"use strict"
const Main = (input) =>{
	let xs = input.trim().split(' ').map(v=>parseInt(v,10));
    let a = xs[0];
    let b = xs[1];
    let ans = 0;
    if(a >= b){
    ans = 1;
    }else{ 
    	for(let i = 20; (a-1)*i+1 >= b; i--){
    	ans += 1;
    	}
    }
    console.log(21-ans);
}
Main(require('fs').readFileSync('/dev/stdin','utf8'));