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 (1.42.0) (judge verdict: Accepted)

// @Problem https://atcoder.jp/contests/abc139/tasks/abc139_b
fn main() {
    let first_line_int :Vec<f32> = read_vec();
    let r = ((first_line_int[1] - 1.0) / (first_line_int[0] - 1.0)).ceil() as i32;
    println!("{}", r);

}

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