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 Ruby (2.3.3) (judge verdict: Accepted)

def main(argv)
  (a, b) = gets.chomp.split(' ').map(&:to_i)
  
  if b == 1 then
    puts 0.to_s
    return
  end
  
  k = 1
  while true do
    s = (k * a) - (k - 1)
    
    break if s >= b
    
    k += 1
  end  
  
  puts k.to_s
end

if self.to_s == 'main' then
  main(ARGV)
end