#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
int main() {
	double X, Y, r;
	cin >> X >> Y >> r;
	X = (X >= 0) ? X : -X;
	Y = (Y >= 0) ? Y : -Y;
	X = (X + Y) / 2.0;
	cout << (int)hypot(hypot(X,X) + r, hypot(X,X) + r) + 1 << endl;;
	return 0;
}