Description

There are n computers that can transmit data to each other, but each computer can only transmit data to at most k other computers per second.
Xiaoming's data is currently on one computer. He wants to know the minimum number of seconds needed to transmit the data to all computers.

Input Format

The first line contains two positive integers n and k (1≤n,k≤10^9).

Output Format

Output the minimum number of seconds needed.

Sample

10 2

3