Calls
In case of fire, call
Announcement
Anya wants to call her friend in another city, and her phone plan has the following pricing structure:
The first a seconds of the call are free.
From the (a+1)-th second to the b-th second, each second costs p kopecks.
Starting from the (b+1)-th second, each second costs q kopecks, where q is less than p.
Anya knows that her conversation will last exactly t seconds. To minimize costs, she plans to divide the call into several parts, with the total duration still being t seconds. She does not want to split the conversation into more than n parts. Determine the minimum total cost of Anya's conversation under these conditions.
Input
The first line of input contains two integers a and b (1 ≤ a < b ≤ 100). The second line contains two integers p and q, representing the cost per second in their respective ranges in kopecks (1 ≤ q < p ≤ 100). The third line contains two integers t and n, indicating the total duration of the conversation and the maximum number of parts Anya wants to split the conversation into (1 ≤ t ≤ 1000, 1 ≤ n ≤ 100).
Output
Output a single number, which is the total cost of the conversation in kopecks.