Time to Fill the Aquarium

Given an aquarium with length l, width w, and height h, and a water flow rate of r cubic units per minute, compute the time required to fill the aquarium completely. The time is calculated using the formula:

\( time = \left\lceil \frac{l \times w \times h}{r} \right\rceil \)

where \( \lceil x \rceil \) denotes the ceiling of \( x \), i.e., the least integer greater than or equal to \( x \).

Be sure to perform the appropriate ceiling division since the water flow might not perfectly fill the aquarium in an exact number of minutes.

inputFormat

The input consists of a single line containing four space-separated integers: l w h r, representing the length, width, height of the aquarium, and the rate of water flow (in cubic units per minute) respectively.

outputFormat

Output a single integer representing the time (in minutes) required to completely fill the aquarium.

10 5 2 10

10