Theatre Square

Description

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

What is the least number of flagstones needed to pave the Square? It's allowed to cover the surface larger than the Theatre Square, but the Square has to be covered. It's not allowed to break the flagstones. The sides of flagstones should be parallel to the sides of the Square.

Input

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

Output

Write the needed number of flagstones.

Sample Input

Input

6 6 4

Output

4

代码如下：

package com.njupt.acm;

import java.util.Scanner;
//每次做题的时候，都会想一下女神章泽天·····然后就动力十足
public class A {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		
		long n , m , a;
		n = scanner.nextLong();
		m = scanner.nextLong();
		a = scanner.nextLong();
		
		long count = 0;
		int totalSpace = 0;
		
//		double oneSpace = a * a;
		long theatreSpace = n * m;
		
		
		long length = n % a == 0? n/a:n/a+1;
		long width = m % a == 0 ? m/a:m/a+1;
		
		count = length * width;
		System.out.println(count);
		
		
		
	}
}