#include <bits/stdc++.h>
 
using namespace std;
 
#define speed ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define rall(x) x.rbegin(), x.rend()
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define mp make_pair
#define pb push_back
#define F first
#define S second
#define nl '\n'
// #define int long long 
 
typedef long long ll;
typedef unsigned long long ull;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
typedef long double ld;
 
const int N = 1e6 + 5;
const int inf = 1e9+123;
const ll INF = 1e15 + 5;
const int mod = 1e9 + 7;
const int P = 31;

ll n, m, k;

void solve(){
    cin >> n >> m >> k;
    ll x = (n + k - 1) / k;
    ll y = (m + k - 1) / k;
    cout << x * y << nl;
}

signed main() {
    speed;
    int T = 1;
    // cin >> T;
    while(T--)
        solve();
}