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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
int main()
{
  int a,b,c;
  scanf("%d%d",&a,&b);
  int i = 1;
  c = 0;
  //a:差し込み口の数/タップ
  //b:欲しい差込口の総数
  //c:差込口の数
  //i:タップの数
  //具体的に想像すると4口/タップだとして
  //4:1,7:2,10:3,13:4,,,
  //2タップ目以降差込口-1で増えていく
  if (a >= b)
  {
    printf("1\n");
  }
  else
  {
    while (c < b)
    {
      c = a+i*(a-1);
      i++;
    }
    printf("%d\n",i); 
  }
}