CF 1A.Theatre Square

比较简单的，问一个 n X m 的矩阵中 最少要放多少个  a X a 的方块；

按边比较，如果倍数就是n/a，否则n/a+1；

每天来CF水一水，更健康点；

贴题：

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 test(s)

input

6 6 4

output

4

#include <iostream>
#include <cstdio>
#include <string.h>
using namespace std;
int main()
{
	long long n ,  m , a ;
	long long sum,x,y;
	while(cin>>n>>m>>a)
	{
		if(n%a==0)
		{
			x=n/a;
		}
		else 
		{
			x=n/a+1;
		}
		if(m%a==0)
		{
			y=m/a;
		}
		else y=m/a+1;
		sum=x*y;
		cout<<sum<<endl;
		}
	return 0 ;
}