#define _USE_MATH_DEFINES	//M_PI
#include <iostream>			//std::cout, std::cin
#include <string>			//std::string
#include <vector>			//std::vector
#include <valarray>			//std::valarray	数値のみの一次配列
#include <algorithm>		//std::sort
#include <time.h>			//localtime_s
#include <cstdlib>			//abs
#include <cmath>			//abs, pow, sqrt, sin, cos,
#include <fstream>			//std::ifstream
#include <iomanip>			//std::setprecision
#include <random>			//std::random(C++11)

int main(void) {

	
	//test用
	//std::ifstream in("test.txt");
	//std::cin.rdbuf(in.rdbuf());

	int X, Y, L;
	std::cin >> X >> Y >> L;

	int com = 0;

	if (Y != 0) {
		com += abs(Y / L);
		if (Y%L != 0) {
			com++;
		}
		if (Y < 0 && X != 0) {
			com++;
		}
	}

	if (X != 0) {
		com++;
		com += abs(X / L);
		if (X%L != 0) {
			com++;
		}
	}

	std::cout << com << std::endl;

}