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.Collections.Generic;
    using System.Collections;
    using System.IO;
    using System.Linq;
    using System.Text;
    using System;

    namespace cysharp_test
    {
        class Program
        {
            static void Main (string[] args)
            {
                new Program ().solve ();
            }

            void solve ()
            {
            int[] ab = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
            int A = ab[0];int B = ab[1];

            Console.WriteLine((B + 1) % A);

            Console.ReadKey ();
            }

        }
        struct Vector2
        {
            public Vector2 (long x, long y)
            {
                this.x = x;
                this.y = y;
            }

            public long x, y;

            public static Vector2 operator + (Vector2 a, Vector2 b)
            {
                return new Vector2 (a.x + b.x, a.y + b.y);
            }

            public static Vector2 operator - (Vector2 a, Vector2 b)
            {
                return new Vector2 (a.x - b.x, a.y - b.y);
            }

            public static Vector2 operator * (Vector2 a, long scala)
            {
                return new Vector2 (a.x * scala, a.y + scala);
            }

            public static bool operator == (Vector2 a, Vector2 b)
            {
                return (a.x == b.x) && (a.y == b.y);
            }

            public static bool operator != (Vector2 a, Vector2 b)
            {
                return !(a.x == b.x) && (a.y == b.y);
            }

            public override int GetHashCode ()
            {
                return (int) (x + y);
            }

            public override bool Equals (object obj)
            {
                if (!(obj == null) && obj is Vector2)
                {
                    return (this == (Vector2) obj);
                }
                else return false;
            }

            public override string ToString ()
            {
                return ("(" + x + "," + y + ")");
            }
        }
    }