Military Enlistment

Jinjin, who has reached the age of military service, wants to apply for the Republic of Korea Air Force recruit program. To be accepted, he needs bonus points, and because the Air Force has become more popular recently, he must collect at least $M$ points through volunteer work or blood donation.

There are $N$ days left until the application deadline. On day $i$, he can take part in volunteer work that gives $s_i$ bonus points. He can donate blood on any day from $1$ to $N$, and each donation gives him $A$ bonus points. However, after a donation, he cannot donate blood or do volunteer work for $D$ days, counting the donation day itself, so that he can rest enough.

Jinjin dislikes blood donation, so he wants to collect at least $M$ bonus points while donating as few times as possible. Find the minimum number of blood donations needed to collect at least $M$ bonus points by the application deadline.

The first line contains two integers $N$ and $M$, separated by a space, where $N$ is the number of days left until the deadline and $M$ is the bonus points needed to pass. ($1 \le N \le 1000$, $1 \le M \le 10^7$)

The second line contains $N$ integers $s_1, \cdots, s_N$, separated by spaces, where $s_i$ is the bonus points from volunteer work on day $i$. ($1 \le s_i \le 1000$)

The third line contains two integers $A$ and $D$, separated by a space, where $A$ is the bonus points from one blood donation and $D$ is the number of days of rest needed after a donation. ($1 \le A \le 10000$, $1 \le D \le N$)

Print the minimum number of blood donations needed to collect at least $M$ bonus points.

If it is impossible to collect at least $M$ bonus points, print -1.