Problem Background

Dundun invites you to share sausages equally.

Problem Description

There are $n$ sausages that need to be evenly distributed among $m$ tasters.

Each cut can divide a sausage into two parts. The goal is to use the fewest cuts to achieve the required distribution. Determine the minimum number of cuts needed.

Input Format

The input consists of a single line with two positive integers $n$ and $m$.

Output Format

Output a single line indicating the minimum number of cuts required.

Sample Input and Output

Sample Input #1

2 6

Sample Output #1

4

Sample Input #2

3 4

Sample Output #2

3

Sample Input #3

6 2

Sample Output #3

0

Notes

Sample Explanation

Sample 1 Explanation

There are 2 sausages and 6 tasters. Each sausage is divided into three parts, requiring 4 cuts in total.

Sample 2 Explanation

There are 3 sausages and 4 tasters. The sausages are cut into $\tfrac{3}{4}$. The first three tasters get $\tfrac{3}{4}$ each, and the last taster gets $3 \times \tfrac{1}{4}$.

Data Range and Constraints

For all test cases, it is guaranteed that $1 \le n, m \le 100$.

Note

This problem is translated from COCI2013-2014 CONTEST #1 T2 KUŠAČ.

见题面 Input 部分

见题面 Output 部分