Calls#1162
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Calls

1 second
64 megabytes
Very easy

In case of fire, call

Announcement

Anya wants to call her friend in another city. Her phone plan has the following pricing structure:

  1. The first seconds of the call are free.

  2. From the (a+1)-th to the -th second, each second costs kopecks.

  3. Starting from the (b+1)-th second, each second costs kopecks (q < p).

Anya knows that her conversation will last exactly seconds. To avoid paying extra, she decides to make several calls with a total duration of . She does not want to split the conversation into more than parts. Determine the minimum total cost of Anya's conversation under these conditions.

Input

The first line contains two integers and (1 \leq a < b \leq 100).

The second line contains two integers and , the per-second costs in their respective ranges, in kopecks (1 \leq q < p \leq 100).

The third line contains two integers and — the total duration of the conversation and the maximum number of parts into which Anya wants to split the conversation (1 \leq t \leq 1000, 1 \leq n \leq 100).

Output

Print a single integer — the minimum possible total cost of the conversation in kopecks.

Examples

Example 1

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