Farmer Bob is buying cereal boxes at his local grocery store, which are priced in the following way:

• The first $M$ cereal boxes cost $C$ dollars each
• For every $M$ boxes purchased, the price of any subsequent boxes is increased by $I$ dollars

Bob only has $Q$ dollars to spend. What is the maximum number of cereal boxes he can buy?

Constraints

For all subtasks:

• $1\le M,C,I\le {10}^9$
• $1\le Q\le {10}^{12}$

Input Specification

The only line of input contains four integers $M$, $C$, $I$ and $Q$.

Output Specification

Output the maximum number of cereal boxes Bob can buy.

Sample Input 1

2 1 3 35

Sample Output 1

7

Explanation for Sample 1

The prices of the cereal boxes Bob can buy are $1$, $1$, $4$, $4$, $7$, $7$ and $10$ dollars respectively.

Sample Input 2

1 15 1 10

Sample Output 2

0