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)

using System;
using System.Linq;

namespace atcoder {
    class Program {
        static void Main (string[] args)
        {
            ABC139.PowerSocket();
        }
    }

    class ABC139
    {
        public static void PowerSocket()
        {
            var s = Input.getIntArray();
            int a = s[0];
            int b = s[1];

            int tap = 0;
            if(b<=a)
            {
                tap=1;
            }
            else
            {
                double tmp = (b-a)/(a-1);
                tap = (int)(Math.Ceiling(tmp)) + 1; 
            }        

            Console.WriteLine(tap);
        }   
    }

    class Input {
        public static int[] getIntArray () {
            string[] s = Console.ReadLine ().Split (' ');
            int[] num = s.Select (x => int.Parse (x)).ToArray ();
            return num;
        }
        public static long[] getLongArray () {
            string[] s = Console.ReadLine ().Split (' ');
            long[] num = s.Select (x => long.Parse (x)).ToArray ();
            return num;
        }
        public static string[] getStringArray (int n) {
            var s = new string[n];
            for (int i = 0; i < n; i++) {
                s[i] = Console.ReadLine ();
            }
            return s;
        }
    }

}