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: Wrong Answer)

use proconio::{fastout, input};
#[allow(unused_mut)]
#[fastout]
fn main() {
    input! {
        a: usize,
        b: usize
    }
    if b <= a {
        println!("1");
        return;
    }

    for i in 1..20 {
        let n = (a - 1) * i;
        let n = a + n;
        if b <= n {
            println!("{}", i + 1);
            return;
        }
    }
}