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: Wrong Answer)

use std::io;

fn main() {
    let mut s = String::new();
    io::stdin().read_line(&mut s).ok();
    let v: Vec<i32> = s.split_whitespace().map(|n| n.parse().ok().unwrap()).collect();
    let a = v[0];
    let b = v[1];
    if b == 1 {
        println!("0");
        return;
    }
    if b == a {
        println!("1");
        return;
    } 
    let r: i32 = b / a + 1;
    println!("{}", r);
}