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: Wrong Answer)

# 空白区切の入力を数値(整数)の配列で返す
def gets_i_list()
  gets.chomp.split(" ").map(&:to_i)
end

A, B = gets_i_list

count = 1
total = A
while true
  break if total >= B
  count += 1
  total = (A * count) - (count - 1)
end

puts count