#include <stdio.h>

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include <random>
#include <chrono>
#include <queue>
#include <functional>
#include <iostream>
#include <queue>
//#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define ld long double

const ll maxn = 2e3 + 1, maxm = 1e7 + 1;
const ll mod = 1500000059, mod2 = 998244353, inf = 1e9, block = 550, hb = 1000012337, base = 1000050017;
const ld eps = 1e-3;

ll n, m, k;
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    cin >> n >> m >> k;
    cout << ((n + k - 1) / k) * ((m + k - 1) / k);
}












