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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

import Control.Applicative

main :: IO ()
main = do
  { [a, b] <- readLineInputs
  ; print $ solve a b
  }

{- |
>>> solve 4 10
3
>>> solve 8 9
2
>>> solve 8 8
1
-}
solve :: Int -> Int -> Int
solve a b = iter a b 1 0
  where
    iter a b c d = if b <= c then d
      else iter a b (pred c + a) (succ d)

readLineInputs :: Read a => IO [a]
readLineInputs = map read . words <$> getLine