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 Rust (1.15.1) (judge verdict: Accepted)

use std::io;

fn main() {
	let mut buf = String::new();
	io::stdin().read_line(&mut buf).expect("");
	let mut iter = buf.split_whitespace();
	let a:i32 = match iter.next().unwrap().parse() {
		Ok(n) => n,
		_ => panic!(""),
	};
	let b:i32 = match iter.next().unwrap().parse() {
		Ok(n) => n,
		_ => panic!(""),
	};
	let mut ret = 1;
	let mut cnt = 0;
	while ret < b {
		ret = ret - 1 + a;
		cnt = cnt + 1;
	}
	println!("{}", cnt);
}