Madara, as you know, is not generally a person to work-out. But recently his girlfriend told him to get in shape. So he started going to the gym everyday.

He knows that he must do at least N number of push-ups in a day. If he is unable to do N push-ups altogether, he does them in different sets. He knows he can do at max A push-ups in the same set. Every time he does a set, he becomes a little tired and hence does D number of push-ups less in the next set. But no matter how tired he gets, he is capable of doing M number of push-ups at the least.

What is the minimum number of sets in which Madara can complete his daily goal?

INPUT:

The first line contains an Integer T, the number of test cases. Each test case consists of four integers - N, A, D and M.

OUTPUT:

For each test case, output an single Integer denoting the minimum number of sets on a new line.

CONSTRAINTS:

1 <= T <= 100

1 <= A, N <=1000

1 <= D <= 500

5 <= M <= 100