#define _USE_MATH_DEFINES
#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<cmath>

#define rep(i, n) for(int i = 0; i < (int)(n); i++)
using namespace std;

int main() {
	int x, y, l;
	int x_ori;
	int count = 0;
	bool flag = false;
	cin >> x >> y >> l;

	
	if (y >= 0 && x>=0) {
		count += (y%l == 0 ? y / l : (y + l) / l);
		if (x != 0) {
			count++;
			count += (x%l == 0 ? x / l : (x + l / l));
		}
	}else if (y >= 0 && x <= 0) {
		count += (y%l == 0 ? y / l : (y + l) / l);
		if (x != 0) {
			count++;
			x *= -1;
			count += (x%l == 0 ? x / l : (x + l / l));
		}
	}else if (y<=0 && x>=0) {
		count++;
		count += (x%l == 0 ? x / l : (x + l) / l);
		if (y != 0) {
			count++;
			count += (y%l == 0 ? y / l : (y + l) / l);
		}
	}else if (y <= 0 && x <= 0) {
		count++;
		count += (x%l == 0 ? x / l : (x + l) / l);
		if (y != 0) {
			count++;
			count += (y%l == 0 ? y / l : (y + l) / l);
		}
	}
	cout << count << endl;
	return 0;
}