Codeforces 1A

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#include <iostream>
#include <algorithm>
#include <numeric>
#include <bitset>
#include <vector>
#include <stack>
#include <cstdio>
#include <cstring>
#include <cmath>

using namespace std;

#define fe(i, a, b) for (int i = int(a); i <= int(b); i++)
#define fu(i, a, b) for (int i = int(a); i < int(b); i++)
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef pair<int, int> pii;
#define pb push_back
#define mp make_pair

int main()
{
    long long n, m, a;
    cin >> n >> m >> a;

    cout << ((n + a - 1) / a) * ((m + a -1) / a) << endl;
    return 0;
}