Link: Problem - A - Codeforces

time limit per test: 1 second

每次测试限制时间: 1秒

memory limit per test: 256 megabytes

每次测试限制内存: 256MB

input: standard input

输入：标准输入

output: standard output 

输出：标准输出

Theatre Square in the capital city of Berland has a rectangular shape with the size n × m meters. 

首都伯兰的剧院广场呈正方形，大小为n * m 米。

On the occasion of the city's anniversary, a decision was taken to pave the Square with square granite flagstones. Each flagstone is of the size a × a.

在城市的周年庆的时候，决定用方形的花岗岩石板铺设广场。每块石板的大小是 a * a。

What is the least number of flagstones needed to pave the Square?

铺设广场最少需要多少块石板？

It's allowed to cover the surface larger than the Theatre Square, but the Square has to be covered.

允许覆盖比剧院广场更大的表面，但必须覆盖广场。

It's not allowed to break the flagstones.

不能打破石板。

The sides of flagstones should be parallel to the sides of the Square.

石板的边需要平行于广场的边。

Input

输入

The input contains three positive integer numbers in the first line: n,  m and a (1 ≤  n, m, a ≤ 109).

输入一行，包含3个整数:n、m和a (1 ≤  n, m, a ≤ 109).

Output

输出

Write the needed number of flagstones.

写出需要的石板数量。

Examples

例子

input

输入

6 6 4

output

输出

4