#include<iostream>
#include<string>
using namespace std;
int main()
{
	int n,m,a;
	cin>>n>>m>>a; 
	
	int max1=-1;
	
	for(int num=0;num<=999999;num++)
	{
		if(a*num <= n  )
     	{
		    if(num>=max1)
		       max1=num;
		    else
		       break;
	    }
	}
	
	int max2=-1;
	
	for(int num=0;num<=999999;num++)
	{
		if(  a*num <= m )
     	{
		    if(num>=max2)
		       max2=num;
		    else
		       break;
	    }
	}
 	cout<<max1*max2<<endl;
	 
	return 0;
}
 
  
//推荐方法
#include <stdio.h>
 
int main(void)
{
    long n, m, a;
 
    scanf("%ld%ld%ld", &n, &m, &a);
 
    printf("%ld\n", (n / a) * (m / a));
 
    return 0;
}