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)

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
  let mut s = String::new();
  std::io::stdin().read_line(&mut s).ok();
  s.trim().split_whitespace()
    .map(|e| e.parse().ok().unwrap()).collect()
}

fn main() {
  let ab: Vec<f64> = read_vec();
  let ans = ((ab[1] - ab[0]) / (ab[0] - 1.0)).ceil() + 1.0;

  if ab[1] == 1.0 {
    println!("{}", 0);
  } else {
    println!("{}", ans);
  }
}