Problem B: Peter's Smokes

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. The input is terminated by end of file.

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: University of Alberta Local Contest