Right now she actually isn't. But she will be, if you don't solve this problem.
You are given integers $*n*$, $*k*$, $*A*$ and $*B*$. There is a number $*x*$, which is initially equal to $*n*$. You are allowed to perform two types of operations:
- Subtract 1 from
$*x*$. This operation costs you$*A*$coins. - Divide
$*x*$by$*k*$. Can be performed only if$*x*$is divisible by$*k*$. This operation costs you$*B*$coins.
What is the minimum amount of coins you have to pay to make
x
equal to
1
?
Input
The first line contains a single integer $*n*$ ($1 ≤ *n* ≤ 2·10^{9}$).
The second line contains a single integer $*k*$ ($1 ≤ *k* ≤ 2·10^{9}$).
The third line contains a single integer $*A*$ ($1 ≤ *A* ≤ 2·10^{9}$).
The fourth line contains a single integer $*B*$ ($1 ≤ *B* ≤ 2·10^{9}$).
Output
Output a single integer — the minimum amount of coins you have to pay to make $*x*$ equal to $1$.
Note
In the first testcase, the optimal strategy is as follows:
- Subtract 1 from
$*x*$($9 → 8$) paying 3 coins. - Divide
$*x*$by 2 ($8 → 4$) paying 1 coin. - Divide
$*x*$by 2 ($4 → 2$) paying 1 coin. - Divide
$*x*$by 2 ($2 → 1$) paying 1 coin.
The total cost is $6$ coins.
In the second test case the optimal strategy is to subtract 1 from $*x*$ $4$ times paying $8$ coins in total.
样例
9
2
3
1
6
5
5
2
20
8
19
3
4
2
12
题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。