Codeforces -- 1A -- Theater Square

#include <iostream>
#include <math.h>

using namespace std;

int main(int argc, char* argv[]){
    long double n,m,a;

    cin>>n>>m>>a;

    long long res = (long long)(ceil(n/a) * ceil(m/a));

    cout<<res;
 return 0;
}