#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <iomanip>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
using namespace std;
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
#define LONG_INF 100000000000000
int main() {
	int x, y, z;
	cin >> x >> y >> z;
	int ans = abs(x) / z;
	if (abs(x) % z != 0) ans++;
	ans += abs(y) / z;
	if (abs(y) % z != 0) ans++;
	if (x != 0) {
		ans++;
	}
	if (y < 0) {
		ans++;
		if (x == 0) {
			ans++;
		}
	}
	cout << ans << endl;
	return 0;
}