CF--1A Theatre Square

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.

Examples

input

6 6 4

output

4

题意：

给一个nm的矩形广场，在这块场地上铺上aa大小的地板，广场的边缘要和地板重合，不可打破地板，求铺满地板需要最少的地板数

AC——Code

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
			long n = sc.nextLong();
			long m = sc.nextLong();
			long a = sc.nextLong();
			long ans=((n-1)/a+1)*((m-1)/a+1);
			System.out.println(ans);
			sc.close();
	}

}