广场维修

#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>

using namespace std;

int main(){
    int n, m, a;
    cin >> n >> m >> a;    
    int c = n / a;
    int k = m / a;
    if(n % a > 0) ++c;
    if(m % a > 0) ++k;
    cout << c * k;
    return 0;
}