A. Cakes

Vitaliy wants to buy exactly $n$ cakes. He has two purchasing options:

1. Buy 1 cake for 1 coin.

2. Buy $k+1$ cakes for $k$ coins.

Determine the minimum number of coins Vitaliy needs to spend to purchase exactly $n$ cakes.

Input

The input consists of a single line containing two integers $n$ and $k$ ($1\le n,k\le 10^{18}$), where $n$ is the number of cakes to be purchased and $k$ is the number of coins required for the second type of purchase.

Output

Output a single integer representing the minimum number of coins needed to buy exactly $n$ cakes.

Examples

Note

In the first example, Vitaliy can buy 3 cakes for 2 coins and then buy 1 cake twice for 1 coin each. This results in a total of $2+1+1=4$ coins.

In the second example, Vitaliy can simply buy 1 cake for 1 coin.

Scoring

Solutions that correctly handle the constraints $1\le n,k\le 10^5$ will earn 20% of the total points.