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 PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
  fscanf(STDIN, "%d %d", $A, $B);
  $ans = 0;
  for($i = 1; $i <= 20; $i ++){
    if($i == 0 && $B == 1){
      break;
    }else if($B - $A <= 0){
      $ans ++;
      break;
    }else{
      $B = $B - $A + 1;
      $ans ++;
    }
  }
  echo "$ans\n";
?>