## Problem Description

Peter has *n* cigarettes. He smokes them one by one keeping all
the butts. Out of *k* > 1 butts he can roll a new cigarette.

How many cigarettes can Peter have?

## Input

Input is a sequence of lines. Each line contains two integer
numbers giving the values of *n* and *k*.

## Output

For each line of input, output one integer number on a separate line
giving the maximum number of cigarettes that Peter can have.

## Sample Input

4 3
10 3
100 5

## Sample Output

5
14
124

## Source

Albert 2001