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

typedef complex<double> P;

double x,y,r;
int ok(int D){
	vector<P> p;
	p.push_back(P(-D,0));
	p.push_back(P(+D,0));
	p.push_back(P(0,-D));
	p.push_back(P(0,+D));
	double a = 10000, b = -10000;
	double c = 10000, d = -10000;
	for(int i = 0 ; i < p.size() ; i++){
		p[i] *= P(1,1) / sqrt(2);
		a = min(a,p[i].real());
		b = max(b,p[i].real());
		c = min(c,p[i].imag());
		d = max(d,p[i].imag());
	}
	P q = P(x,y);
	q *= P(1,1) / sqrt(2);
	if( a <=  q.real()-r and q.real()+r <= b )
		if( c <=  q.imag()-r and q.imag()+r <= d )
			return true;
	return false;

}
int main(){
	
	cin >> x >> y >> r;
	for(int i = 0 ; i <= 1000 ; i++){
		if( ok(i) ){
			cout << i << endl;
			break;
		}
	}
}