CodeForces Solution of 1A. Theatre Square

#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;

int main()
{
    double n, m, a;
    while(scanf("%lf%lf%lf", &n, &m, &a)==3)
    {
        printf("%0.0lf\n", ceil(n/a)*ceil(m/a));
    }
}