#include <bits/stdc++.h>
using namespace std;

int main() {
    long x,y,l;
    cin >> x >> y >> l;
    if(y==0){
    	if(x==0){
    		cout << 0 << endl;
    	}else{
    		cout << 1+(abs(x)+l-1)/l << endl;
    	}
    }else if(y>0){
    	if(x==0){
    		cout << (abs(y)+l-1)/l << endl;
    	}else{
    		cout << 1+(abs(y)+l-1)/l+(abs(x)+l-1)/l << endl;
    	}
    }else{
    	cout << 2+(abs(y)+l-1)/l+(abs(x)+l-1)/l << endl;
    }
	return 0;
}