#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
int main(){
	int x, y, l,x1;
	cin >> x >> y >> l;
	x1 = x;
	int sa=1,count=0;
	while (sa> 0){
		if (x == 0)break;
		sa = abs(x) - l;
		x = sa;
		count++;
	}
	sa = 1;
	if (y == 0)cout << count << endl;
	else {while (sa > 0){
		sa = abs(y) - l;
		y = sa;
		count++;
	}
	if (x1==0)cout << count << endl;
	else cout << count + 1 << endl;
	}
	return 0;
}