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 main() {
    let (a, b) = {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line);
        let a: Vec<i64> = line.split_whitespace().map(|a|(a).parse().unwrap()).collect();
        (a[0], a[1])
    };

    println!("{}", if b == 1 {0} else {std::cmp::max(0, b - 2) / (a - 1) + 1})
}