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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

// ABC139 B - Power Socket
// 20190902

using System;

namespace B
{
    class Program
    {
        static void Main(string[] args)
        {
            // Console.WriteLine("Hello World!");
            //入力受け取り
            string str = Console.ReadLine();
            string[] arr = str.Split(' ');

            int A = int.Parse(arr[0]);
            int B = int.Parse(arr[1]);

            //計算
            int count = 1;
            int C = A;

            if (B == 1)
            {
                Console.WriteLine(1);
            }
            else
            {
                while (C < B)
                {
                    C += A - 1;
                    count++;
                }

                //出力
                Console.WriteLine(count);
            }

        }
    }
}