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: Accepted)

using System;

namespace abc139_2
{
    class Program
    {
        static void Main(string[] args)
        {
            // input
            string[] str = Console.ReadLine().Split(' ');
            int a = int.Parse(str[0]);
            int b = int.Parse(str[1]);

            // output
            int ans = 0;
            bool flg = true;
            int tmp = b - a;

            if(b == 1)
            {
                ans = 0;
                flg = false;
            }

            if (flg)
            {
                if (tmp <= 0)
                {
                    ans = 1;
                    flg = false;
                }
                else
                {
                    ans++;
                }
            }

            while(flg)
            {
                tmp -= a - 1;
                if(tmp <= 0)
                {
                    ans++;
                    break;
                }
                ans++;
            }

            Console.WriteLine(ans.ToString());

        }
    }
}